NGC 7006

NGC 7006 in Delphinus is one of my favorite globular clusters. It's not as spectacular as M5, M3, M13, M22, at least from a visual sense, but understanding it's semi-remoteness compared to the others makes it special. I have a fond memory of my first glimpse of this cluster back in 1988 with my Celestron C8 SCT. With my '83 (second edition) copy of Peterson's Field Guide to the Stars (which I still have) and using the setting circles of the Super Polaris, I found the small smudge of light of the globular even through the light pollution dome of Philadelphia to the Southwest. Distance measurements to NGC 7006 since the field guide's printing have been refined with new estimates of 135,000 ly compared to 185,000 ly referenced in the book.

NGC 7006 in Delphinus

Type: Globular Cluster

Magnitude: 10.6

Apparent Size: 2.8'

Distance: 135 kly

Physical size: ~120 ly

Half-mass Rad. ~43 ly

Date acquired: Sept. 22, 2025

Sky Brightness ~17.95 mag/arcsec^2

Ambient Temp: 69F / 20.5C

Camera: Starlight Xpress SX-694 (2x2 binning) 

Guider: Starlight Xpress Lodestar off-axis.

Scope: Astrotech AT10RC @F/8 (2000 mm)

Mount: Losmandy Titan w/Gemini-2

Filters: Astronomik L, R, G & B type 2c.

Exposures: L= 27 x 120 sec

Acquired, calibrated, stacked (avg) in Astroart 9

Processing Notes:

Calibrated with Flats, Bias & Defect Map

Linear Gradient removal

Multiscale Denoise to remove some background LP noise

Log stretch

The annotated image labels some galaxies in the 16-18 mag. range.

Palomar 5 (UGC 9792)

Palomar 5 in Serpens

Type: Globular Cluster

Magnitude: 11.8

Apparent Size: 8'
Distance: 75.6 kly
Physical size: ~152 ly

Date acquired: May 31, 2024

Sky Brightness ~18.25 mag/arcsec^2

Ambient Temp: 58F- 56F

Camera: Starlight Xpress SX-694 (2x2 binning) 
Guider: Starlight Xpress Lodestar off-axis.
Scope: Astrotech AT10RC @F/8 (2000 mm)

Mount: Losmandy Titan w/Gemini-2

Filters: Astronomik L type 2c.
Exposures: L= 13 x 120 seconds
Acquired, calibrated, stacked (Median) in Astroart 8

Processing Notes:

Calibrated with Flats, Bias & Defect Map

Linear Gradient removal to correct for light pollution.

Images were taken (mistakenly) without the cooler enabled so the subs were noisy. Bias, Flats and Darks were subsequently taken with the roughly the same temperature to salvage the data. The image is clipped considerably to mask the noise. Median stacking was used since a few satellite trails spoiled some images. There is also a noticeable elongation of the stars which may have been due to mis-collimation or poor polar alignment.

NGC 6656 (M22)

NGC 6656 (M22) Globular Cluster in Sagittarius
Date acquired:  July 27, 2019
Camera: Starlight Xpress SX-694 (2x2 binning)
Guider: Starlight Xpress Lodestar off-axis.
Scope: Astrotech AT10RC @F/7.8 (1987mm)

Mount: Losmandy Titan

Filter: Astronomik L Type 2c
Exposure 20x60" (20 minutes)
F.O.V. = 21.58' x 17.29' @.94" arc/pixel
Acquired, calibrated, stacked (avg) in Astroart 7
Altitude Mid-Exposure 22deg
Moon Age: 25 days (not in sky)

NGC 6656 (M22)

Magnitude: 5.1
Object Type: Class VII Globular
Apparent Size: 32'
Distance: 10.6K ly

Physical size: ~100 ly

I don't have any info. on the weather conditions when the images were acquired but the following pics show the location of M22 from my backyard location along with the amount of light pollution I image through.

1/4" exposure

8" exposure