Recently I was browsing an online astronomy journal when I came across an advertisement for a remote imaging site in Chile: Chilescope.com. It was an attractive home page and of course being an avid astroimager I know about Chile, arguably the hottest property right now and home to all the latest and greatest ground based telescopes in the world. The Atacama Desert, driest place on Earth, could be the best observing site without actually being in outer space! Now I already own and operate a remote observatory in Mayhill NM, the birthplace of remote imaging so why would I be interested in anything else? Probably the main interest lies in the fact that I cannot observe the southern hemisphere’s sky from here! The fact that it is Chile adds a certain mystique to the whole picture. I decided to look into it further. The observing site is located in a remote part of Northern Chile. The nearest town is Ovalle, Chile which really isn’t that close to the Atacama Desert. It’s actually a good 700 km to the south.
X marks the spot where Chilescope is located. Atacama region is about 3 times the distance to the “Chile” label , north, on the map
Ok, perhaps I was a little disappointed, but after further research I discovered it still lies in an area in the North where the weather is superb and the climate is still quite dry. The site sits at a modest elevation of 5000 feet so quite a bit lower than anything in the Atacama region. The project was started by a group of astronomers in 2013 in collaboration with the University of Santiago.
Three observatories that were built are available for use. Two of them house identical telescopes and equipment, consisting of extremely fast (F3.6) ASA 20” Newtonians with direct drive mounts and FLI 16803 cameras.
Telescope 2 and 3 are 20″ ASA newtonians equipped with 4″ Wynne correctors for a corrected field of 50mm at an amazing F/3.6! An FLI Proline 16803 camera is used with a 10 position filter wheel. The mount is a direct drive equatorial mount which does not require meridian flip.
The third observatory houses a 1 meter RC scope! The site is directed toward amateur astronomers but also caters to professionals who are looking for quality telescope time. I am not generally familiar with “pay for play” telescope rental sites except for perhaps itelescope, which has, in my opinion, a very complex user interface and payment structure. This by contrast is extremely clean and simple. The cost for use of one of the Newtonians is 60 dollars per hour which is quite a bit cheaper than what I have seen for other sites. They provide the usual “Moon discounts” for imaging in moonlit skies. They also credit observers for mechanical problems and even bad frames. My estimate was that you could conceivably do a decent tricolor image project with the fast optics and discounts for perhaps around $400 or so. I then looked at the calendar of availability expecting a long wait time but was surprised to see that I could start observing the next day! Of course the next thing to inspect was the images that were obtained by users. These were absolutely tremendous APOD quality images all the way! I was sold! A chance to image the famous Centaurus A galaxy and other renowned southern hemisphere gems! Luckily I had just sold some astroimaging equipment so I had some discretionary funds to test this out. My first target was of course Centaurus A! Payment is through PayPal either from your own account or via credit card. You have to register of course first and then your payment shows up as “chile points” where 1 point equals 1 US dollar.
The user interface is very simple and they walk you through everything.
The weather is recorded here as “unsuitable” but that is because it is during the day. You set up your times based on calendar availability. You have to check with your favorite planetarium program when your object will be visible. I use Stellarium, which actually has Ovalle, Chile in their database! They do not image below 30 degrees so if your set up times are problematic either because of object visibility or conflicts with sunset or sunrise you will get an error message. Also of note is the late sunset time, around 9 oclock or so.
User planning page showing available observing time and overall image session
Remember it is Fall down there and they do not observe Daylight Savings! Currently you can easily image for 4-5 hours. They do reserve about 2 hours or so for non imaging functions. All of these details are explained both on the site and in a downloadable PDF . If you have any experience at all imaging the set up page is a snap. You enter the RA and Dec coordinates of your target, enter the number of subs you want to take, filter, binning, exposure time, how often you want to focus and even dithering. That’s it! When your session starts you get an email with a link to the session log which you can follow. At the end of your session your files are available for download. You can also download your bias, darks and flats at any time for free. They update their flats every week and darks every 2 weeks.
And now the results! This is a single 20 minute raw luminance image at 1:9 scale. The image analysis below shows the average FWHM is about 2.3 with this image scale (1 arc sec per pixel) which is close to the lowest resolution I have seen here:
They tell you that their system is optimized for 20 minute exposures so that’s what I chose. On my first session there was a technical glitch and seeing was not good that night so I did get a 30% refund based on the number of frames I lost and/or had to throw out. Their customer service is outstanding. Emails regarding any issues are handled anywhere from within 1 hour to maybe a few hours but always resolved before the next imaging session. I checked all of my images in Pixinsight and my conclusion was that resolution in general was outstanding. On the best nights it was typical to obtain single 20 minute subs with an average FWHM in the 1 arc sec range. Less than great seeing was in the low 2’s. As mentioned the system is very fast and as a result is perhaps undersampling a bit with only a 1 arc sec per pixel image scale. The focal length of 1900mm (corrected) at F/3.6 demands precision focusing as the critical focus zone is a mere 20-30 or so microns! Consistent perfection in star quality is probably not realistic given this type of optical set up with the need both for absolutely perfect focusing with a minimal error margin, and field correction for a 20 inch Newtonian! As a result about 1/5 of the images I obtained had oval appearing stars in the very corners of the field at full resolution but I actually only had to discard a few that were frankly bad. The rest were acceptable to where I felt after processing would not be noticeable. The corrected field is 50mm so it is quite large considering the size of the optics! The other problem that came up was occasional failed plate solving which caused shifting of the target off center. These frames were credited back to me no questions asked. I was actually relieved to see that I am not the only remote observatory operator that has issues to deal with! The one variable there which seems to cause no trouble at all is the weather. I am into my second week of imaging and I still have not seen a single cloud on their all sky cam!
All sky cam near sunset.
All sky cam just before the start of imaging. The Milky Way is in full bloom! You can actually see Orion well to the north in the right upper quadrant. I believe that the Large Magellanic Cloud is visible in the south just to the right of center
In conclusion I would highly recommend this site for anyone who wants to image targets that can only be seen or optimally seen in the Southern Hemisphere. The cost is not prohibitive and the fast optical system makes it possible to obtain enough quality data in a reasonable time frame. The seeing at this site in Chile is excellent, and the resolution and image quality obtained make it well worth the expense, not to mention the excitement of seeing these amazing objects which we cannot see from Northern lattitudes! The user interface is very simple and customer service is superb. While you will have to throw out some subs like we all do at times, most of these will not come at additional cost. Best of all…they add 20% to your initial deposit if you are a Cloudy Nights online astronomy forum member!
Thanks for reading!