March 11, 2018
Setting up the William Optics GT81 tonight with my new ZWO ASI071MC camera. I'm also trying out--again--the 30mm apt/135mm fl guide scope with the ZWO ASI120MM-S, this time with the camera threaded directly to the scope, reducing the backfocus a few more millimeters. This will be my first time out with the new main camera, and I've been anxious to see what it can do for almost a week. The ASI071MC is a color CMOS camera with an impressive dynamic range, TEC cooling, 16MP APS-C sized Sony sensor with 4.8μ pixels. The idea is to have the new color camera compliment the Atik 414EX monochrome CCD I normally use. The Atik with the Nikon 180mm f/2.8 lens has almost the same field of view as the ASI071MC with the William Optics GT81. (The Atik + Pentax Takumar 200mm f/4 is even better). You can't tell with the way I've configured the top dovetail rail and guidescope, but the plan is to be able to run both cameras simultaneously with similar FOV, one color, the other with narrowband filters, in some ways doubling my productivity.
February 27, 2018
Setting up the William Optics GT81 tonight, with the Atik414Ex Mono CCD. There's a big bright moon out there tonight, so I'm not sure what I'm going to shoot. I'm mostly testing out a few things. First, a 2" UHC/LPR filter I've had for a few years--and I don't think I've used it for almost that long. The other is my smaller, short focal length guide scope--135mm FL (that black tube on the other side of the main refractor).
January 10, 2018
This is my "astro cart", which allows me to get everything connected, bolted on, balanced, and ready to go while still in the house--before I go out in the freezing temps. I can roll it right up to the back door that leads out to the deck. One of the real advantages of the iOptron CEM25P is its light weight to carrying capacity specs. The lower total weight allows me to pick up this whole setup (OTA, camera, counter-weights and all) and carry it to the pier. (That's my William Optics GT-81 APO next to the AstroTech, right side of the cart).
Getting ready for some potential clear skies tomorrow or the next day, and I'm doing the prep setup with the Atik414EX on the AstroTech RC scope--f/7.2 with the focal reducer/field flattener. I have some smaller targets picked out, and might even go back for more of the Horsehead nebula (with the RC's longer focal length), as well as other interesting stuff in Orion.
Note on the iOptron CEM25P: The mount only weighs 10.4 lbs (4.7 kg), but has a payload capacity of 27 lbs (12.3 kg) without the counterweights. Total weight of the William Optics refractor, imaging train (Atik CCD, filter wheel, filters, and extensions), guide scope and camera, and various other gear ends up around 15 lbs (6.8 kg), and with the AstroTech it's another 5 lbs, so still well under the 27. That's where you're going to get the best guiding and alignment results--not pushing that capacity boundary. (Just for comparison, my Orion Atlas EQ-G mount weighs 54 lbs (24.5 kg) just by itself, and has a payload capacity of 40 lbs(18 kg)--so yeah, it can carry more, but there's no way I can handle setting up except when everything is in pieces).
My Refractor Setup as of October 5, 2017
December 25, 2017
My Winter Astro Setup, essentially the same William Optics GT-81 - iOptron CEM25 combo, with the addition of the iOptron Tri-Pier Adapter, some 6x8 aluminum plates off eBay, and one treated 4x4 post from Home Depot.
The good side of winter and astrophotography is it’s usually dry on clear nights--and “clear” really means clear in terms of astronomical seeing, atmospheric turbulence and all that. Downside is that it’s freakin’ cold. Tonight it’s supposed to get down to about -8°C (about 20°F), pretty cold to be out for a long time, but not painfully cold.
Here are a couple shots of my setup for tonight--and possibly the rest of the winter. (William Optics GT-81, CEM25P EQ mount, Atik414Ex mono CCD, WO 50mm guidescope with ZWO ASI120S-MM guide cam, INDI/KStars/Ekos observatory control). What’s cool is that I can unbolt the mount with the pier adapter and aluminum base plate (they’re all bolted together) from the 4x4 post and top plate, and carry in the entire setup--mount, scope, cameras, etc. What I especially like about this is the ease with which I can setup and tear down each night. The whole thing remains balanced and ready to go, with polar alignment reduced to very fine adjustment to zero in on the NCP.
Note on my other mount: I probably won’t use my Orion Atlas EQ-G mount until spring when things start to warm up, and that’s based on the weight of the Atlas and the low temperatures--with ice adding some difficulty to the setup process. (Yeah, I don’t want to lug around this monster with any probability of slipping, landing on my back, and having to catch fifty or sixty pounds of metal out of the air before it kills someone). The average winter low in New Hampshire is around -12°C, and the average winter high temp is still below 0°C (around 30°F). It’s not unusual for things to get down to -20 to -30°C (-10 to -20°F). We’re still in December, so early in the season, but we’re already getting repeated snow storms interspersed with temps above 0°C (32°F). We typically get a few days of warmer weather here and there, snow and ice melting weather, but there haven’t been enough of them to make a dent in the accumulating snow and ice we have in the yard, driveway, or back deck. We just ended yesterday (the 25th) with another 6 inches or so. When there’s ice, lighter is better.
Beyond the meridian test
I love the iOptron CEM25P mount. It's center-balanced, lightweight, very accurate if you don't push the 27lb limit, and easy to work with under almost any app that uses ASCOM or INDI. I regularly shoot 5 - 10 minute guided subs without issue, even 20 minute subs, depending on the target. Besides capacity, the one difference that stands out from my Orion Atlas EQ-G is how far the CEM25 can take things beyond the meridian. This is a quick shot--yes, I know it's not directly centered, but it does give a rough post-meridian estimate of 20° or so. That's enough when you're chasing M42 with those last ten minutes of exposures. I do think the Atlas has more room here though, but I'll have to test that. (This is my wide-field setup--Nikon lens, QHY primary cam, ZWO guide cam)
# This is a config file for the Astrometry.net 'astrometry-engine' # program - it contains information about where indices are stored, # and "site policy" items. # Check the indices in parallel? # # -if the indices you are using take less than 2 GB of space, and you have at least # as much physical memory as indices, then you want this enabled. # # -if you are using a 64-bit machine and you have enough physical memory to contain # the indices you are using, then you want this enabled. # # -otherwise, leave it commented-out. #inparallel # If no scale estimate is given, use these limits on field width. # minwidth 0.1 # maxwidth 180 # If no depths are given, use these: #depths 10 20 30 40 50 60 70 80 90 100 # Maximum CPU time to spend on a field, in seconds: # default is 600 (ten minutes), which is probably way overkill. cpulimit 300 # In which directories should we search for indices? add_path /usr/share/astrometry # Load any indices found in the directories listed above. autoindex ## Or... explicitly list the indices to load. #index index-219 #index index-218 #index index-217 #index index-216 #index index-215 #index index-214 #index index-213 #index index-212 #index index-211 #index index-210 #index index-209 #index index-208 #index index-207 #index index-206 #index index-205 #index index-204-00 #index index-204-01 #index index-204-02 #index index-204-03 #index index-204-04 #index index-204-05 #index index-204-06 #index index-204-07 #index index-204-08 #index index-204-09 #index index-204-10 #index index-204-11 #index index-203-00 #index index-203-01 #index index-203-02 #index index-203-03 #index index-203-04 #index index-203-05 #index index-203-06 #index index-203-07 #index index-203-08 #index index-203-09 #index index-203-10 #index index-203-11 #index index-202-00 #index index-202-01 #index index-202-02 #index index-202-03 #index index-202-04 #index index-202-05 #index index-202-06 #index index-202-07 #index index-202-08 #index index-202-09 #index index-202-10 #index index-202-11 #index index-201-00 #index index-201-01 #index index-201-02 #index index-201-03 #index index-201-04 #index index-201-05 #index index-201-06 #index index-201-07 #index index-201-08 #index index-201-09 #index index-201-10 #index index-201-11 #index index-200-00 #index index-200-01 #index index-200-02 #index index-200-03 #index index-200-04 #index index-200-05 #index index-200-06 #index index-200-07 #index index-200-08 #index index-200-09 #index index-200-10 #index index-200-11