GRAS Telescopes - Splitting Crosshairs

A Dozen Remote Telescopes? Why so many? Tubes, glass, wires, balanced metal, silicon chips and bits. What’s the difference which GRAS telescope I use? A picture is a picture after all.

A big difference actually, especially if you want results that will please and satisfy your astronomy needs. Be it gathering photons for epic stellar portraits or vital scientific data. The telescope you use should match its mission.

Putting on the Lab Coat

GRAS-001 Science PlatformLets take G1 and G2 first up as an example. This amazing pair of Takahashi 12” (300mm) Mewlon reflectors are unique on the GRAS network. They are science workhorses.

Both are LONG focal length (3572mm) and operating at a native focal ratio of almost f12. These are amongst the longest focal lengths in the GRAS fleet, where most of the systems have moderate to wide angle field of views. This fact alone brings with it some real challenges for the remote telescope driver.

But they are wonderful science platforms fitted with Photometric UBVRI filters used for photometry with very sensitive NABG CCD cameras.

NABG refers to a CCD camera that has no special circuit to inhibit blooming. NABG cameras have a linear response to light. They generate a charge that accurately reflects the amount of light striking each pixel. This makes NABG cameras ideal for situations involving measurement of the incoming light (photometry).

G1 & G2 are a real handful when it comes to automation and remote operations. The long focal length and thus relatively dim images in the G1 FoV - M27narrow field of view can make plate solving (fine pointing) and guide star selection somewhat of an ordeal but not impossible. It really becomes a matter of just how populated with suitable pointing/guidance candidates the target zone is.

The current conditions at the observatories need to be taken into account as well. G1 & G2 don’t like gusts or windy nights when guide or focus stars can be knocked around on chips making a hard job even harder. Experienced GRAS drivers see these symptoms and adjust session plans or move across to another telescope for the mission at hand.

Most problems with long focal length imaging are overcome with some clever GRAS programming and the fact that most science users use short exposures anyway, ranging from 60 to 180 seconds so the telescopes run unguided quite well most of the time. These telescopes are excellent machines for the job they are meant to do. Not so pretty but its great data in your images. That’s what matters on a science mission.

The Best of Both Worlds

GRAS-005 Hybrid MissionsThe majority of GRAS telescopes are muscular, multi purpose platforms. Capable of both fine imaging and a good deal of science as well. Notable systems are G5 and G11 in New Mexico. These telescopes are fitted with a great variety of filters including Luminance-Red-Green-Blue (LRGB), Narrowband as well as a full compliment of photometric filters on each. Big Wheels indeed.

G5 is one of the busiest remote telescopes on the GRAS Network. It allows its many drivers to gather simply amazing images with its moderate wide angle FoV and the razor sharp Takahashi optics. Coupled with its ST10XME CCD NABG camera, G5 can go very deep and wide with ease and very high reliability. But care should be taken by those new to NABG cameras.

Keep your exposures short if very bright stars are in your target FoV. Trial and error can help you fine tune exposure times as well and the right processing tools to repair the image and remove blooming if necessary.

Most of the GRAS imaging systems do carry ABG cameras and blooming is not an issue. These systems may feature some photometric filters for science but being hybrid platforms they are also set up for astro imaging with LRGB and/or Narrowband filters that are the basic tools for astrophotographers.

G9 in AustraliaG9 is a 12.5” RCOS telescope based in Australia. It has a full house of UVBRI filters teamed with an ST10 NABG CCD. G9 is the prime science platform in the southern hemisphere at this time. But good old G9 is also capable of brilliant narrowband imaging with several APOD prizes under its belt. Its a highly reliable telescope which has  enabled countless GRAS drivers in the northern hemisphere to capture southern glories as well as valuable science data. It has often been used in Hubble Space Telescope support missions.

G14 is a great platform for wide angle imaging and can also do valuable science with its V filter. This little Takahashi FSQ gets a lot of use from science users scanning for asteroids and working on variable stars, and nothing can match its very wide FoV portraits and its performance on the sky’s larger extended objects such as large nebula, clusters, bright comets and even catching fast moving Near Earth Objects.

The Big Boys

Now lets have a closer look at the larger remote telescopes. We at GRAS label a system as ‘large’ when the mirrors cross the 14” barrier.

GRAS-011 New MexicoGRAS has three large aperture telescopes on its network at the moment with more to come in the near future. G11 is a 20” 0.58M CDK Planewave reflector based at Mayhill, New Mexico. G7 and G17 are based in Nerpio, Spain. Both are similar 17” 0.43M CDK Planewaves. These telescopes are all simply amazing platforms utilising the latest in telescope design and technology. If you really want to go ‘Deep Space’ then these will do the job with ease.

But there are a few things I can tell you about them here.

The G11 ‘AartScope’ is the supreme photon hunting science machine on the GRAS network. This instrument can deliver pin-sharp images even during 300-600 second unguided exposures, reaching magnitudes as low as 21.5 without too much effort.

In fact GRAS Tech has deliberately disabled the guiding on G11 because its performance is THAT GOOD. The Ascension mount provided by its manufacturers at Planewave has simply stunning accuracy in both pointing and tracking. It is impressive and GRAS will be taking delivery of more Ascension mounts in the near future.

This ability to track unerringly, unguided for long periods saves users so much time in imaging overheads that the value of this system makes it worth booking well ahead. Its very BUSY and on most clear nights it is being used for long periods doing everything from variable star work to exo-planet research and stellar portraiture with its sensitive and cool running FLI CCD camera delivering with reliability and no fuss.

G7 and G17 at AstroCamp - GRAS in SpainAcross the Atlantic Ocean and perched high in the south eastern alps of Spain is the European based AstroCamp - GRAS Observatory. Here live three GRAS telescopes G7, G17 and G16. This observatory has been set up by skilled members of the La Palma Observatories complex atop the Canary islands. Some Grande Telescopios based there!. So they know a thing or two about optics and running an observatory.

G17 and G7 are large Planewaves and each has a CCD to suit a mission.

G7 is a 17” Hybrid platform utilising a large format STL11000M CCD. This is an ABG camera so it lends itself to long exposures on a wide variety of targets. G7 is populated with photometric RVB filters so it stands well in the science stakes as well as a set of narrowband units for amazing Hubble palette imaging. Care however should be taken when using G7 for photometry as its CCD is of the ABG variety. So users should make sure they don’t saturate the image as result may not be linear.

Record holder GRAS-017Quasar via G17G17 in Spain is a unique telescope. In fact it currently holds the world record for the most distant object imaged by an amateur.  Its FLI ProLine E2V CCD47-10-1-109 CCD has ‘extended red’ sensitivity when compared to standard CCD’s. Giving it a very ‘Near Infrared’ mission profile.

If you want to bring out stars hidden in nebula or chase targets that are very faint, then this scope will do the job. Its extremely sensitive, so much so that OVER exposure becomes an issue and users should take care since its CCD is of the NABG variety.

It also carries some specialist filters for narrowband imaging with Custom Scientific filters including those for Sulfur III and Helium II. Resulting in unique images of some familiar targets. G17 also has a set of BVRI photometric filters so it can handle science missions with ease. A truly hybrid astronomy platform.

Remote Telescope Driving - Hints and Tips

Hello fellow GRAS Drivers!

Ahhh…PerfectionAfter another week of action behind the scenes at GRAS, I thought I would pass along a few pointers on just how to maximise your time on a remote telescope and get the most from the GRAS System.

You would be surpised how many user images I see as part of my duties. I get “Usage Reports” Emailed to me every day from all the systems and they simply amaze me at times.

Most are very pleasing for a support crew to see and give us a great amount of pleasure. Clear focused images and nice round stars. Bliss.

But the odd “Clunker” does reach me on occasion as well. An image with fuzzy and/or trailing stars. I don’t like these at all. I pull my hair out at times like this. What to do? My process goes something like this:

1. I check the user’s Log during the image
2. I check the weather during the time of the image
3. I check the targets Altitude
4. I check for proximity to a bright Moon
5. I check the image exposure time
6. I check other images from just before and after the user’s own session
7. I check the sugar levels in my coffee
8. I check the telescope system logs for faults during focus, guidance or pointing subroutines
9. I check for any possible faulty calibration frames involved
10. I check to see if our GRAS technician is awake for a fast Skype consultation
11. I check accounts and return user points
12. I check all this then I keep an eye on that system for a while

A bump in the nightDuring this routine I usually can find something to pin the blame on. A focus or guiding failure caused by cloud, wind, roof closure due to weather, close proximity to a bright Moon, frozen fog or a system error that can lead to a telescope crashing and burning. Well not quite burning, but its a bad thing.

Yet a system failure can also be a positive, when we can correct it and prevent it from occurring again. This is why sending us a prompt Support Message can be very helpful to all involved.

A nearby bright moon can effect a session in several ways. The telescope may not be able to find a guide star or focus properly. Moonglow can also washout an image if its too close, making the saved calibration data ineffective or cause reflections within the telescope optics. We suggest you give the moon at least 50 degrees clearance. This is where a good planetarium application comes in handy. Narrowband filters will negate the moon nicely as well.

Windy conditions at the remote sites can at times cause tracking errors, this is a rare occurrence, but sudden gusts can and will effect some of the telescopes. At times like this the domes usually shut automatically.

Foremost on my mind is the telescope user. Apart from a waste of points and time, they have possibly lost a time critical observation or a chance to image something really special. I can understand the frustration they must feel when a horrible mess appears on the preview screen or in the Email or their FTP folder. What to do?

Hey! The moon is in the way!Well the majority of the time our more experienced drivers know exactly what went wrong and they correct the flaw in the plan and carry on, but what of those not so accustomed to remote telescope imaging? They may indeed get a very bad impression of our systems and telescopes in general.

They deserve the best we can deliver to them as far as internet astronomy goes.

“Satisfaction Guaranteed”  as our motto says. And we mean it!

So apart from my investigations and the odd refund, what can a GRAS user do to avoid frustration and spamming GRAS support? A few simple and easy steps can do the trick for you.

• Plan your remote telescope session carefully
• Check the weather often
• Understand the remote telescope
• Testing the system before you start a long session
• Be Patient with the telescope
• Dont be shy and Contact Support if you feel the need

Moonglow! yuck!Planning means knowing your target is at a favorable elevation and at least 45 degrees from a bright moon. Science users dont need to worry so much about moonglow. Having a planetarium program really is vital. Also try to use the ‘Advanced’ mode if you need precise pointing. ‘Regular’ and ‘Express’ modes do skip some important phases in the telescope scripts such as focus or plate solving to an exact location. But also use less time.

Weather needs to be monitored. We provide numerous links to our weather data and wide angle Sky Cameras. SO USE THEM! Refresh often and be aware.

Understanding a remote telescope means knowing its limits and strengths. At times you will want a wide Field of View (FoV)  and a fast f ratio. Others a more narrow and close up view of your intended target. I would not recommend a new user chasing a comet or fast moving NEO asteroid with G1’s narrow FoV for example. G14 would do the job much better and more easily. 

More information can be found if you log into a telescope (no charge until you start an image) and click the “Telescope Info” link to the bottom left. It shows the telescope field of view (FoV), CCD type, filters assignments etc.

Satelite tracks during a very long exposureAlso try to avoid use of overly long exposures in one single shot. It actually gains you very little in detail or depth. The way a CCD works your much better off using a series of shorter shots and stacking them to increase your signal. GRAS recommends you limit your exposure to 600s or less. 900s if your an advanced user and certainly not anything over 900 secs.

I have seen images attempted on our systems of over 7000 seconds! Not good. Your images will be subject to guiding errors, passing cloud, wind, satellite tracks, cosmic ray strikes, climate change etc.

GRAS suggests exposure times of: 60, 120, 180, 300 or 600 seconds. We have matching calibration data for these times.

Testing the System means just that, its optional, but worth while if you have a long session in mind. Before you trigger a long sequence of multi-filter shots, test that the telescope is in good order. It does not take long and often will save you having to start again if things do  go a bit wrong. Support does check every telescope before the domes open but we are dealing with very complex equipment and software so gremlins can sneak past our security now and then. If you do find a problem let Support know as soon as you can.

1. Check the SkyCams!
2. Check the elevation and position of your target. (is the moon very close?)
3. Input your target in the ACP interface
4. Set up a 30 second exposure with a Clear or Lum filter
5. Watch the System Status readout during the test
6. Check the Jpeg preview for quality
7. Check the SkyCams again!

Did everything work well? To center the object for stacking later, may we suggest not using the ‘Express Mode’.  The other modes will ‘plate solve’ the field of view and then precisely postion the telescope, albeit at a small time overhead, before starting your image sequence. 

Great! Now your ready to start that epic imaging session.

Go back and input your sequence. Check its what you want then hit “Aquire”

Be patient with the system as it does its job. Autofocus and Pointing subroutines can take some time to achieve. The telecsope will try to find the best guide stars and focus candidates to work with. In a depleted star field this may take a few minutes and while the system status may Appear to be doing nothing at times due to internet lag etc, it is working hard in the background to give you the best result. But if your in doubt, send us a SUPPORT email.

But dont forget, CHECK the WEATHER!  Keep an eye on the SkyCams. Abort if you feel its getting scary, you can always try or continue again later. Contact Support if your not happy with the results of your session as soon as possible too. We are happy to return your points.

There you go. Before long you will become accustomed to using a remote telescope on the other side of the world, something professional astronomers do every night and now you can call yourself a real GRAS Driver!

Cheers!

Some days are Flat out and Dark. But I'm not Bias

What can I say about your average Calibration frame? They are sorta dull to look at.

On my back yard Meade i take a few darks and the odd Bias on rare occasion, Flats? Rarely, yet here I am at my GRAS workstation, monitors spread around me, On one I’m trying to keep an eye on the systems and on top of things, and on the other monitor  I have gigabytes of fresh calibration data to plow through! Its a living.

Can you imagine what is involved in gathering these vital data files from over a dozen different telescopes spread across the globe? Its no picnic. But it has to be done. Often.

As the sun sets at our remote observatories they roll open to collect their daily quota of skyflats, then later maybe a few hours of Darks and Bias if the roof or domes are shut, then again more skyflats at dawn. Your GRAS telescopes never really sleep at all.

We actually have a very sophisticated AutoFlat (AF) application running on all the telescopes. NO, you cant find it at the local store, it was written just for us and our rather heavy duty needs.

Lets add it all up.

Our sample remote telescope, lets say G12 in Australia, will take a set of Dusk flats later today. Red-Green-Blue, Clear, Ha-SII-OIII, and if the scope is set up for science duties it will also have a set of U-V-B-R-I onboard its filter wheel as well. So that can be up to 12 filters to run through before its too dark and the stars pop out.

The G12 AF wakes up and asks a few questions every afternoon, it has a binary conversation with the other GRAS software sharing its hard drive. What time is it? Where is the sun? Is the roof open yet? Do we need a special filter order today? Do I have to send or pickup any new files? It then swings into action and takes charge. It slews the G12 telescope to the best part of the eastern sky, it opens its CCD eyes and has a little peek.

Is the sky too bright? Then AF will wait a little while longer and carefully countdown as the sun dips ever lower towards the western horizon. If its too dark it must be cloudy and the roof will still be closed. So AF goes back to sleep for a while.

But when AF finds the sky is bright enough to make a start it will trigger a script in the ACP Control software. It Chills the camera, selects a filter and begins to fire 3 images at an automatically corrected exposure length. This flat frame image is capturing the unavoidable optical gunk that collects in a telescope that works hard for a living.

Dust is the enemy. Tiny dust motes and other particles that penetrate to the filters or CCD will show up as dark donuts of various sizes on the white flat field images the CCD collects. These flat frames will ‘cancel’ them out of a user’s image during realtime calibration and post processsing stages.

So G12, our sample system has now gathered between sunset, during the night and finally at dawn all its filtered flats plus a wide selection of dark frames at five standard exposure times, 60-120-180-300-600 seconds. The darks have been recorded at both 1x1 binning and 2x2, as have the bias taken along with them. Three of every flavour.

This calibration data, from each of the 14 or so remote telescopes on the GRAS system is then automatically collected by AF, named, compressed and sent via the internet to make its way to the correct folders in my workstation. About 4 Gb of files. All packaged and ready for inspection and conversion into master calibration frames.

The number of files I have to chew through visually to check for quality can get a bit mind numbing.  As its final task for the day, AF takes the fresh master files from my workstation and transmits them back the way they came for installation on the telescopes and into the customer FTP folder for your use when needed.

Things can and do go wrong at times. But your results are worth the work. Black Coffee helps too :)

See? At GRAS your remote telescopes are never too idle. Thanks AF,  I for one appreciate you!