Posts Made By: ian edwards

i have a reoccuring, though intermittent problem when taking wide-field shots by piggypacking my film SLR (Canon Rebel 2000) with a 28-80mm lens.

often, but not always, my photos show stars not as pin-points but as coloured cirles several millimetres across, often with blurbed edges.

i assumed that this was because i had not focussed to infinity but vigilent checking prior to taking a shot did not solve the problem.

next, i considered that perhaps the focusser was slowly rotating downwards (and away from the infinity position) with gravity and
mount motion during the duration of the shot. so i started using an elastic hair-tie to hold the focusser in the infinity position once the shot was composed.

this 'appears' to hold the lens in position, however, i am still producing photos with blurbed, round circles of light rather than
pinpoints. the cirles are indeed circular so i believe that tracking is accurate enough and not the source of the problem. especially
since other shots taken during the same session will be ok.

i know that a picture says a thousands words but i not currently in a position to access a slide scanner.

i am hoping that the experience of the group may recognise my issue and give me any pointers, other possible points of failure, or a list of tests to perform to solve this problem.

thanks in advance,
ian

hi scott,
i image using a refractor and a dob so i dont have much advice to offer other than saying that i, too, use the canon rebel so be sure when you buy the T-ring that you get the EOS version (the rebel is called the EOS300 in other parts of the world) since the camera lense fitting differs from regular canon cameras.

a good and inexpensive place to find a t-ring and other accessories is at:
http://www.agenaastro.com

i know thats not much but i hope it helps,
good luck!!
ian

thanks for the tips. testing infinity in daylight is a good idea, i''ll try this.

i think i need to do a series of test shots at different focal length and apertures and see if i cant find a point that works.

thanks,
ian

hi guys,
the site _looks_ much better. very slick and professional looking design. it would appear that a lot of recoding has also taken place.

from where i sit i am experiencing a slower response than the previous site. it seems to me to be some network latency within your web environment possibly between web server and database server? (yes i do have considerable experience in such matters). i click on a link and it just sits and sits, but when i hit STOP and REFRESH, the web server responds in a timely fashion. i did not experience this on the previous site nor other sites in general.

other comment, it would help if ads for sponsors included their URL.

upshot: great job!!

ian

the problem is that people are very used to NOT paying for material and services online.

yahoo, msn, etc has many astro-forums with large memberships, ebay sells everything known to humankind and then some. astro-news is available everywhere and the number of amatuer websites with great photos and helpful info is beyond count.

if astromart wants to 'own' the online astro-community then they need to develop a business plan and make the investment to accomplish that without the community having to pay the bill.

if astromart is happy to be one of many similar services then they need to re-evaluate the services that are provided and perhaps specialise rather than spreading themselves to thinly.

certainly the classifieds are a clear advantage. but forums, news, etc are, perhaps, not paying for themselves.

i agree with a previous post - apologies to the author for forgetting their name - who suggested eliminating news and forums and required payment for ad placement, leaving the site free for general use.

i would even be happy with astromart making a percentage on each transaction.

ian