Home > Astrophotography > GRAS – Global Rent A Scope – First Light

GRAS – Global Rent A Scope – First Light

It does feel like cheating at first. You should really be out there in the elements connecting everything up amidst a rats nest of wires and cables, balancing the equipment, aligning the mount, locating your objects to image, focussing, imaging, transferring the files, calibrating and processing – or at least you would be if there wasn’t wall to wall cloud, which is what I have had over the last two weeks. I’ve been going slightly crazy looking at all the great images of comet C/2009 P1 Garradd appearing in numerous photogenic pairings as it passes by famous deep sky objects. And then there’s Supernova 2011fe in M101 which has been slowly brightening to its maximum current magnitude of 10.5, rivalling the galactic core for brightness in images. While a few notable images have rolled in from staunch amateurs and their home observatories many people have been using remote telescopes to capture their own visual keepsake of these unique astronomical events.

You soon get over the guilt of going fully remote of course, particularly when you realise that this is how professional astronomers grab their images anyway, just with much bigger telescopes and more sophisticated imaging devices. And even the amateurs are not really roughing it these days. Most of the top imagers have fully automated observatories and merely have to set the imaging targets on a computer and the kit does the rest while they go back to sleep. So don’t feel guilty, just get those images taken any way you can and revel in the fact that full remote automation is even available to the amateur these days.

Many of the remote images I have seen originated from GRAS or Global Rent A Scope http://www.global-rent-a-scope.com/ which has an array of telescopes available in three locations including New Mexico (US), Spain and Australia. So I figured I would initially try the system out on the Free Test Drive offer using GRAS 003 in New Mexico which is a Takahashi TOA 150 refractor (1100mm/ f7.33) paired with an SBIG ST2000 XCM 2 megapixel one-shot color camera. The Test Drive deal gives you 60 points to use which basically gives you about an hour on this setup with the ability to capture 3-4 ten minute (600 second) exposure images. The registration was painless with just basic details collected, then you are sent an activation. After activation an email arrives by return with your unique username and password. You then wait 15-20  minutes for your account to go live on the GRAS servers. When your account goes live you sign in to the GRAS Info Centre where the first thing to do is check if the observatory you are using is in the night portion of the colour day/night animation. Also check if the all sky camera for the observatory shows a clear sky with obvious stars. I then clicked on the G3 telescope when the ‘Available’ message appeared in the constantly refreshing list of telescopes.

The GRAS Info. Center with me on the G3 telescope……

On the Free Test Drive your options are pretty limited once you get to the actual telescope control screen. You can only choose to image a set number of famous objects (all of them Messier objects when I was using the system) from a short list using the One Click Image system. They will all be objects at least 45 degrees above the horizon and if you choose something below that level you will get a message telling you the object is unavailable. To my dismay M101 was out of range at the time (11.20 pm US time) and comet C/2009 P1 wasn’t even listed, so I was left with a fairly mundane list of familiar Messiers.

As the camera is one-shot colour providing a fully RGB calibrated image I decided to target some colourful objects and picked the M27 and M57 planetary nebulas. The exposures are locked at 10 minutes (600 seconds) so you just click on the Submit button next to the image of the object you want to target and off the telescope goes. A scrolling script screen provides detailed feedback on the whole process and after about 12-15 minutes you get the message that the session is complete. The server then automatically calibrates and processes your image for you and sends it as a jpeg file attachment in an email.

The initial single jpeg images you will receive by email are poor quality heavily compressed jpegs weighing in at just 80kb in size and 800×600 pixels. These are just the preview images however and you should shortly receive the zipped FITS files by email or you can download them from the GRAS server using an appropriate FTP client (I use the GRAS recommended FTP Surfer which is free). For a 10 minute exposure the results are quite surprising ! After converting the calibrated FITS file to SBIG RGB in Maxim DL5 and stretching the levels I did a  bit of gentle noise reduction, increased the contrast in the nebula slightly and increased the star colour using Noel Carboni’s Astro Tools plugin in photoshop. There was M27 in glorious (and fairly accurate) colour with plenty of detail in its structure and a nicely dense starfield around it  – I was feeling quite chuffed 🙂  M57 was a bit lost in the widefield image and stared at me like some brightly coloured Saronesque eye, but even that image looked decent after a bit of tidying.

M27 – The Dumbbell Nebula – 10 minutes, one shot colour – processed image

M57 The Ring Nebula – 10 minutes, one shot colour

At this point cloud rolled in and the New Mexico observatories all closed their doors for a few hours. I headed back to GRAS at around 4am US time and most of the telescopes were back online. Wanting to try a different scope I went for the G20 which is a Takahashi FSQ-ED 106mm 530mm / f5 widefield refractor paired with an FLI ML8300-C  8.3 megapixel one-shot colour camera. At this point I should have done my research as I chose M76 The Little Dumbbell nebula to image. This is really too small an object and too distant for these widefield scopes and looks hopelessly lost in a very pretty starfield – lesson learned !

M76 Little Dumbbell Nebula – hugely cropped !

Having now set up Stellarium (version 0.11.0) for the various observatory locations I have researched the correct times to catch M101 and C/2009 P1 more than 45 edgrees above the horizon in New Mexico. I also put the various telescope and camera combinations into CCD Calc 1.5 so that I could see what the field of view for M101 would be (C/2009 P1 FOV confirmed from other peoples images) and GRAS 03 seems to be the telescope for the job.  OK , i’m all ready for another session on GRAS 03 around 3am tomorrow morning UK time, weather permitting in the US. I’ll post up the results tomorrow – wish me luck !

EDIT 4/9/11 – Quick update – it was cloudy all night at the New Mexico location and the domes remained closed – so no images taken !

Categories: Astrophotography
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