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New Observatory help

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stargator's picture
New Observatory help

Retiring soon—so I need a ‘Job’!!!!  OK, I’m new to this forum and I need some advice/direction on some of the finer points on what I need equipment wise, software etc. On the start-off, I would like to get involved with variable star observing and continue with astrophotography full time.  My bride of 20 years is letting me build an observatory at my new home in Flagstaff AZ—I’m one of thoughts fortunate guys that has a ‘dream wife’.  I’ve been an amateur for about 15 years now and am a regular at the star parties in my area. My current workhorse scope is a W/O 110 mm refractor with a Orion star shoot G3 camera. The losmandy G11 works well for my mount. I have a 32” Dob up at my flag home that will be set-up once I retire.  OK! so what’s on the shopping list for the new observatory??  Well, I purchased the new SB paramount 2 as the first item and stopped at that. I would like to get a scope that I can use for both science and astrophotography. I looked at the Plainwave 17” (CDK)—nice scope with a 50mm FOV....big bucks!! Will the doublet lens be an issue for precision photometry?  Cameras—looked at the FLI Proline 16803...great for astrophotography but good for photometry?? Anyone use this camera for this?  Recommendations would be helpfulSmile





WGR's picture

Hello Stargator

Saw you post and question about he CDK-17.  I have one here at Maria Mitchell Obs that we bought.  Used primarily for photometry.  Doublet does not seem to be a problem.  Been a great scope.  If I ever upgraded from my Tak Mewlon 300 CRC, the CDK-17 is on the bucket list.  I was customer #1 for the 17, and it was so finished I could not believe.  You expect a few loose ends on the first one, but it was perfect.  I know a couple more AAVSO folks that have the 17 and the 20.  Highly Recommended.

As for cameras, I think Arne will probably chime in.  Make sure you have an image scale of 2-3 FWHM of the star images for you site.  Flagstaff can be very good.  Somewhere between 0.5 and 1.25 arc seconds per pixel is probably required--depends on your seeing.  I think you want a full frame vs interline for this.  Most of the specs on cameras are way better than you need.  The biggest PT errors will be other things.  Save money for filters, big filter wheel, software, autoguiders, computers, internet, Icron Rangers, Focusers, and of course, AAVSO membership and support.

As an alternative, you could use AAVSOnet remotely as a member benefit for 6 months, until you find out what you really want. 


lmk's picture
A super visual setup


 I have a 32” Dob up at my flag home that will be set-up once I retire.  OK! so what’s on the shopping list for the new observatory??  



A 32" Dob! Thats probably bigger than what most other variable star observers are using. Why not concentrate on using this visually. If you have pretty dark skies, that scope can get you down in the mid-17th mag range easily. Hardly seems much additional need for an expensive CCD setup, it would be mostly redundant, I think.

Mike LMK

stargator's picture
Gary/mike--- thanks for the

Gary/mike--- thanks for the chime in.  good to hear that others are using the 17” CDK. The seeing out here in flag is pretty darn good, especially during the winter months it seems—my wife with her younger eyes can see no discernible twinkle of stars about 15 degrees above the horizon. I would say that the seeing is a good 6-7 mag limit at the zenith for the young eyes, much better than my desert home here in Ridgecrest CA were it gets around 117f in the summer!!  As for the 32’ Dob, it will also be used for deep sky and star work. The Dob preforms marginally here in the desert--we have this strange weather pattern of cold air that comes from Bakersfield and mixes with the hot air from the desert..yuk! But It totally rocks at high elevations, 7/8K feet!  


I am definitely a beginner with the variable star/photometry stuff, but I now have time to ‘re-invent’ myself from my old job and learn something new.  I’ll more than likely get the CDK 17”, it’s a sweet scope. I Still need to study up on cameras—blooming gates, S/N, all that good stuff!!   And yes Gary, I’ll be joining up with the AAVSO!!!  Count me in!!


The Stargator  

hambsch's picture
CCD Camera

Hi Stargator,


I am using an FLI ML16803 as primary photometric CCD camera with AStrodon BVI filters. The camera is very similar to the Proline, but much less heavy. That was the reason to choose the ML over the PL.

The CCD cools very fast, the filterwheel is very reliable, though it has an opening around the motor where dust can enter the housing (very annoying in a dusty area). I have taken several 100000 images without too many problems. Main problems so far encountered are the connections between FW and CCD which is only by 2 screws. If the scope moves a lot (as in my case I do star cycling), the connection gets loose once in a while.

The CCD is very efficient and big and you can observe stars in a brightness range from say mag 8 to mag 19.5 (or even lower). It is more a question of exposure and binning. I most of the time bin 3x3 and I have a 16 inch ODK f/6.8 scope from Orion Optics England, a very similar design as the Planewave. All is set-up remotely. I image on more than 300 nights (really).

I would go for a direct drive mount without gear systems. I have an ASA DDM85. There are others on the market but as far as I know mainly from Europe, so in Dollars the price is higher than for a PM. I do not do autoguiding.

If you have further questions please do not hesitate to ask me.

Josch Hambsch (HMB)

stargator's picture
Josch—Sounds like you

Josch—Sounds like you have a nice professional set-up.   I have been doing some reading up on blooming gates, full well capacity and

so on—what method did you use to find the ‘liner’ region of the CCD before blooming gate roll off on the 16803?   I understand this is

something I need to know when doing photometry?!   I did some playing around with my Orion star shoot G3 camera:  Using Maxim DL, I ran some exposures at different times until saturation,  Maxim DL has this nifty ‘Graph Window’ that I used to plot the response

curve. The star shoot specs call out 50,000 ADU at the approximate sat.  From what I can tell from the plot, looks like things start to roll off at about 25,000 ADU’s—Hummm!  Am I on the right track!


Need to do some more reading tomorrow!!!! 


Thanks again

The Stargator 

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