Alignment and Guiding Experiment

After setting up the telescope I usually do a Celestron AVX all star polar alignment (ASPA) using the visual finder for rough centering then fine centering on the computer screen with the ASI294MC Pro. I thought this might be bit of overkill considering the use of the Orion Magnificent Mini Autoguider. I setup the scope on my 3rd floor patio, as lousy a place for viewing considering no access to Polaris and a tree limited view. The ASPA was performed using the visual finder only starting with  rough north alignment. Jupiter, Saturn were used for alignment and Fomalhaut for calibration star. I usually use two alignment and four calibration stars in the field. Surprisingly only 7' altitude and 7' azimuth corrections were required. Pointing accuracy was less accurate than typical but was good enough to put target on the camera sensor. I had not checked the alignment of the finder with the optical train. This was good enough for M42 but not for NGC2023 so I used precision go to which uses a bright star as a waypoint to the faint target. M42 and NGC2023 with the Flame Nebula and Horsehead Nebula imaged that night appear below. Update: M42 reprocessed for reduced oversaturation.

M42

NGC 2023(center)with Flame Nebula(left) and Horsehead Nebula(right)

Update: A pleasant  start of Orion season surprise. Condo association removed twelve dead trees surrounding my building including the tree right in front of my terrace. Likely the association was prompted by the coming bomb cyclone that will hit Greater Boston with heavy rain and high winds. More sky!! 😀

No light pollution filter

For the first time since acquiring the Starizona Night Owl 0.4x focal reducer I decided to image with the Celestron F/6.4 focal reducer without a light pollution filter(LPF). These images were acquired in 14 to 15 radiance area in increasingly light polluted Frederick, MD vs the 0.5 to 1.0 radiance darkish areas where I image in Harvard MA and in Northern Maryland. Except for the NGC6946 which was imaged with 30s subframes all imaging was done with 15s subframes. I'll be revisiting many of my DSO favorites imaging without the LPF to see if an improvement in signal to noise can be achieved. Update: Globular clusters are reprocessed for less contrast and saturation.

Messier 13

Messier 15

Messier 27 

Messier 56

Messier 92

NGC6946

The Kit as the Brits Call It

I listen to lots of science podcasts while imaging, especially ones from the BBC, The Guardian and Nature; thus my kit comment. Above is the setup just after taking flat frames for the coming night session. Celestron 8, Celestron AVX mount, ZWO ASI294 MC Pro color camera, Starizona Night Owl 0.4x Reducer/Corrector and Orion Magnificent Mini Auto-guider, For power, partially hidden by tripod leg, a Westinghouse iGen160s. Also available a 12v Centech jump starter. During twilight the auto-guider is temporarily swapped for a 50mm visual finder to do the all star polar alignment. Then the auto-guider is swapped back in, wired up and calibrated using stars near the celestial equator.  Update: The Centech is no longer used. The  iGen160s has more than enough juice to handle all the night's power needs.

7-30-2022 Summer Favorites

All of these were acquired with 30s subs. NGC6946, NGC6888 and NGC6823 are averages of 120 subs while NGC6992 and NGC7635 are averages of 60 subs. NGC6823 is actually a new summer favorite that I will return to in the future. I'll be returning to NGC6946, NGC6888 and NGC6823 acquiring 60s subs in hope of bringing out more nebulosity or galaxy.

NGC6946 (Fireworks Galaxy)

NGC6888(Crescent Nebula)

NGC6823, NGC6820

NGC6992 (Eastern Veil Nebula)

NGC7635 (Bubble Nebula)

7-26-2022 : A Comet and Star Clusters

Comet C/2017K2 PANSTARRS

IC4756

NGC 6823

IC4665

IC4725

M11 (Wild Duck Cluster)

M26 (NGC6694)

NGC6709

July 20, 2022 Summer Favorites

All images were acquired with Celestron 8 SCT on AVX mount with ZWO ASI294MC Pro using Starizona Night Owl operating at F/4 and light pollution filter.  Subs for the comet, Sh2-142 and Sh2-155 were 30s typical for the Harvard, MA area. I'll revisit the Sharpless targets with 60s exposures in the future to try to bring out more nebulosity. Exposures respectively for M27(my better half's favorite)  and M13 were 8s and 15s. Update: M13 reprocessed for better contrast. 

M13

Comet C2017K2 PANSTARRS

Sharpless 155

Sharpless 142

M27

Globular Clusters

This is the time of the year to image globular clusters, some of my favorite targets. The bulk of them tend to be low in the southern sky which is a challenge considering seeing and refraction. M13 was included in the previous post. Several others acquired on the same night appear below. M55 was acquired on a later night. Images were averaged from 30x30s subframes acquired at 120 unity gain. Configuration was Celestron 8 , Starizona NightOwl 0.4x focal reducer, ZWO ASI294MC Pro CMOS camera. Update: Images reprocessed with GraXpert stretching and residual gradient removal.

Messier 3

Messier 4

Messier 5

Messier 10

Messier 12

Messier 13

Messier 55