Observing Notes 29th April 2016 - Baader Moon/Skyglow Filter & DSOs

I thought I'd do some DSO photography. I removed the focal reducer and set up with diagonal and Barlow tube without the x2 lens. Instead I attached my Baader Moon/Skyglow filter at the screw-threaded end of the Barlow tube. Attempted 10x30 second exposures of M94, M51 and NGC7203 (the Iris Nebula).

Results once I got back inside were awful, even when the exposures were stacked in Deep Sky Stacker. There simply weren't many stars in the exposures. The filter was robbing me of stars. Don't use this filter for stellar DSOs! Try it on nebulae?

Also, I realised my focussing left a lot to be desired.

P.S. I've just been reading a review of this filter on the Cloudy Nights website, and the reviewer suggests to just try holding the filter in front of the eyepiece (when observing visually), so that you can swap in-and-out and see the difference. Good idea, must try this.

Observing Notes 26th April 2016 - Jupiter (Best Yet) With Double Barlow

Tried imaging Jupiter with a double Barlow arrangement - DSLR with T-adaptor x2 Barlow tube inserted into another x2 Barlow tube and then into diagonal (no focal reducer). Camera was set to video at 25 FPS and 640 x 480px. I noted that the image of Jupiter on the live screen of the camera was noticeably dimmer with the 2 Barlow x4 arrangement than with just a single Barlow, so set shutter speed to 1/30 second and video FPS at 25 (have to turn manual video settings ON Nikon D3200 menu options).

Results were reasonably successful once 3-minute video was stacked in Registax:

Observing Notes 25th April 2016 - DSLR Tripod Photography

I decided to have a few hours without wheeling the big scope out and just try some photography with my D3200 on a tripod in the garden. My site suffers from a lot of light pollution; my visual limiting magnitude is about 4.4 on a good night.

I knew there would be lots of field rotation on a tripod, so I took multiple exposures and used Deep Sky Stacker to stack them together.  I did two runs, one with 10s exposures and one with 20s exposures. The 10s exposures came out better when stacked.

Got some half-decent results:

Cassiopeia, stack of 10 10 second frames, Nikon D3200 with 55mm lens, Hoya "Image Intensifier" filter. Stacked with Deep Sky Stacker, post processed in Photoshop to darken sky background a bit.

Observing Notes 17th April 2016 - First Sight of Mercury

First outing after horrendous week of problems last week involving (1) spraying a big white mark onto corrector using compressed air cleaning can (cleaned off carefully using dilute detergent, cotton buds, Kleenex and deionised water); (2) installing new dew heater system and then getting into big cord wrap trouble, have I wrecked gears/motors?, alignment slewing now miles out); (3) discovering secondary assembly was loose and moving in the middle of the corrector (just tightened up outer retaining ring and tightened collimation screws, collimation should now be shot, secondary no longer in factory-installed position, do I have to remove corrector and put it all back together again?).

(1) Set scope up while not yet dark. Good news - we can focus fine on the road sign about 1/2 a mile away and also have pretty decent lunar views at moderate powers (scope not yet cooled, seeing poor etc.). But we still have a working scope.

(2) GPS alignment. DEW HEATER SYSTEM NOT PLUGGED IN YET, in case there's some kind of electrical problem affecting alignment. GPS align on Capella and Arcturus. Nope - both stars miles out in finder. Both same distance out in finder - scope pointing about 1-2 degrees right/west from stars in azimuth (it was azimuth/RA motor that got strained with the cord wrap problem) although about right in altitude. Sighted stars manually and aligned carefully using reticule eyepiece. Slews to objects (Jupiter etc.) coming in fine.

SAW MERCURY FOR THE VERY FIRST TIME!!! Scope offered it as an option, it was just between my roof and Will's next door. Whoo-hoo! All these years and I've never seen it!!!!

Recalibrated compass (did this last week, didn't help alignment problems) and FOR FIRST TIME recalibrated Alt level sensor using hand controller. Turned scope off and on and then did new GPS alignment. Alignment stars now in finder FOV fine! Was it alt sensor calibration that was the cause of the problem?

(3) Seeing still not too good, so did some lunar prime focus photography. Got first ever images of M13 and and M57. Jumping up and down with joy. New Baader Moon and Skyglow filter on the bottom of the Celestron Barlow T-Adapter (but with the Barlow lens itself removed) prime focus on the back of the scope (in diagonal). The Baader filter seems to work brilliantly for astro-imaging, I couldn' t really see any great differences visually when I tried it out last week, but with 15 sec exposures at ISO 800 in the Nikon D3200 actually got some results!

(4) Seeing seemed to improve, so tried new Duncan mask on front of scope. Saw the expected 3 ringlets when out of focus, then when changing the focus the Y-shape. Swapped to x400 magnification and could clearly see the Y-shape (although it still looks really very small in the FOV). Seeing had deteriorated though and decided now was not the time to start mucking about with collimation and to call it a day (now running out of power, dew heater had drained battery so much that the old girl was just about tracking but was puffing when asked to slew anywhere!)

TODO:

Attempt Duncan mask collimation - need A1 seeing for this.
Buy another battery pack for dew heater. Little trolley to keep all power stuff on and just wheel in-and-out?
Need big roll of Velcro, having a lot of trouble with all these wires getting tangled up in the dark.