Log of Dennis Webb's 100 Arp Galaxy Astrophotos

Home | Gallery | Arp Peculiar Galaxies

Click on the Arp number below in the table  to see the image. 
Explanation of the columns follows the table:

Arp    The catalog number assigned by Halton Arp to his list of 338 fields.

NGC or other name    This is the name of the largest galaxy (assume NGC unless otherwise stated) ) or a collective name commonly used.

Date    The date the image was collected: YYMMDD.  "030415" is April 15, 2003.

Central Time    Time of start of image acquisition. All images were made in the Central Time Zone, with the recording made using official time, which reflects shifts to Daylight Savings Time.  I know I should use UT but the computer and I are happy and reliable on local time.

Camera    Name of astronomical CCD camera used: homemade Cookbook 211 (bought complete off Astromart), later upgraded to Cookbook 245 with Low Dark Current modification, and an excellent Finger Lakes Instruments IMG-1300 borrowed from Andy Saulietis at TSP 2002.  By the way, the Takahashi EM-1 mount was also bought off Astromart.

Focal Length    Focal length of the various optics used:

200mm - a Vivitar telephoto lens at f/3.5, attached to the camera with a floppy homemade fixture to attach to the camera.

440mm - a 5-inch f/3.6 newtonian, optics made and figured by Bob Taylor, telescope made by author, with fabrication help by the remarkable Chuck Shaw.

1250mm - A Celestron C-8 Schmidt Cassegrain (bought off Astromart) with a f/6.3 focal reducer (separately purchased off Astromart).  Evaluated and adapted to my Takahashi mount with help by Chuck Shaw.

2000mm - The same C-8 at f/10 without the focal reducer

Focal Ratio    As stated above

Exposure    Number and duration in seconds of individual exposures.  "36x60" means thirty-six exposures of 60-second duration, that are later combined to make the images.  I have settled on 60 seconds as a maximum exposure given imprecise polar alignment, the "rivets" phenomena from my Cookbook 245 camera, and bright sky background at home.  Most made with the C-8 are autoguided.

Location    Where the image was collected. 

"Houston" means my light polluted residence in the southeast suburbs of Houston, TX. 

"TSP" is the Texas Star Party held annually in May at the Prude Ranch near Fort Davis, Texas. 

"McKavett" is Fort McKavett State Historical Site near Junction, TX, where the Johnson Space Center Astronomical Society gather on expedition twice a year. 

"Smithville" is observing companion Dick Miller's observatory near Smithville, TX, close to Austin.  Dick and I went to our first TSP together in 1992 and we have shared many happy nights of visual observing and imaging over the years.

"Danciger" is Al Kelly's Observatory, a celebrated astronomical center two hours southwest of Houston. My first visual observing sessions and many of my early images were made there and I owe a great deal of my joy and skill to Al's patience and support.

"Johnson City" is a friend's house.  We went up on spur of the moment, I got the exposure started and got exactly 2 exposures before the clouds came in.  First discovered banding interference with my camera.  Dang.  Attempts to fix the interference later weakened some internal wires leading to failure of the camera at the next TSP.  Double dang.

Seeing/Transp    Astronomical conditions during image acquisition: Excellent, Good, Fair, Poor.

This page produced July 24, 2003 by Dennis Webb
All images copyright 1999-2003 by Dennis Webb