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Posts Made By: Tom Licha

July 14, 2002 01:20 PM Forum: CCD Imaging and Processing/Solar System

CCD polar alignment?

Posted By Tom Licha

Mike,

I permanently installed GEM last year.

Firest I used the polar alignment scope. Then I changed to CCD exposures. I increased focal length wit a 3x barlow lens. This brings out any tracking errors mor easy.

I took pictures starting from 1 min. to longer and longer. In between I corrected the alignment. I did it with trial and error. 50% chance to get the direction right is OK. Then keep this direction until there is no further improvement...

BTW: By doing it with real CCD exposures you are also correcting for the error of refraction in the atmosphere. Hence this method is even better than theoretically perfect north pole alignment.

The procedure took me one whole night, but I did not have to touch it since 15 months. My rest error over appr. 1 hour is only periodic error of worms.

CU
Tom
http://www.licha.de/AstroWeb 49° 13' 54" N


July 14, 2002 07:06 PM Forum: CCD Imaging and Processing/Solar System

ST7e Focus with CFW Color Wheel

Posted By Tom Licha

Hi Sam,

with the FS60C I had to add 30mm of extension tube to reach focus with Homeyer filter wheel and HX916. Taks tend to have *a lot of* back focus.

Sorry that I do not have exactly the same equipment...

Clear skies
Tom
http://www.licha.de/AstroWeb 49° 13' 54" N

July 19, 2002 03:13 PM Forum: CCD Imaging and Processing/Solar System

CFW-8 SBIG vs True Tech. CWN-3175D

Posted By Tom Licha

Hello Sam,

dont know these both but please consider also Homeyer Wheel. Here is a review I wrote:

http://www.licha.de/AstroWeb/reviews_fullsize.php3?iRevId=16

I love it, because its so flat (thin).

CU
Tom

July 21, 2002 05:19 AM Forum: CCD Imaging and Processing/Solar System

cameras

Posted By Tom Licha

Hi Merlin,

here is a link to a comparison calculator for CCDs. So far only SBIG and SXPress cameras are included. The C8 is included too.

http://www.licha.de/AstroWeb/articles_fullsize.php3?iHowTo=9

I hope it is useful
CU
Tom

July 27, 2002 05:33 AM Forum: CCD Imaging and Processing/Solar System

Any Got the Draco Dwarf? Challenge?

Posted By Tom Licha

Hello Kwang,

the Draco Dwarf is on my list for best placed objects these days:

http://www.licha.de/AstroWeb/calendar.php3

Mag is only 11.9 and because it is *so* big this should be a challenge.

If you would like to be the first one who photographed it and published it on my site you are very welcome.

http://www.licha.de/AstroWeb/contact.php3

I think, I will give it a try too.

Whats your aperture? And speed?

July 29, 2002 09:29 AM Forum: Equipment Talk

2" Focuser for Newt With compression holder.

Posted By Tom Licha

Hello David,

I am using a 1,25 version of what you need. It is perfect. And the brass ring is holding and centering much better than the one screw version. They have a 2" version too.

I can only provide a link in german laguage.

http://www.baader-planetarium.de/zubehoer/mechadap/t2_01.htm

The piece has part number 240 8140 (#17) and is called Okularklemme Deluxe 2"

The company Baader is working von Celestron with Ultima eyepieces and the MPCC corrector.

The german word for brass is Federbronze.

CU
Tom
mehr freude. http://www.licha.de/AstroWeb 49° 13' 54" N

July 29, 2002 02:59 PM Forum: CCD Imaging and Processing/Solar System

Digital camera with long exposure capability

Posted By Tom Licha

Luis,

I tested the Nikon D1 which is available second hand relatively cheap now. Can shoot 30 secs. There is a bit of noise at 30 secs but it is OK. It can be easily coupled like traditional SNR body with t-ring.

CU
Tom

September 3, 2002 09:33 AM Forum: Equipment Talk

planetary scopes

Posted By Tom Licha

Hello Larry,

I aggree!

The best shots on the planets ever made are all with *big* mirrors, mostly perfect collimated Newtons with small diagonals. These guys reach detail of 0.1 arcsecs now (in their photos) which will *never* be visible in a perfect 6" flourite apo. I only know one frenchman with very good planetery results with a Meade SCT 10".

My flourite Baby-Takahashi with only 60mm diameter is very good and sharp on planets (with 6x Barlow-projection) but my mediocre Discovery Newton 10" f/4 and my very good Starsplitter 10" f/6 is *much* better at good nights.

Thanx
Tom
mehr freude. http://www.licha.de 49° 13' 54" N

September 12, 2002 08:04 AM Forum: Film Astrophotography - Imaging and Processing

What happened here? (long)

Posted By Tom Licha

My tip: Straylight (from street lamp?) with ghost reflections. I had almost the same and built extension tube from thick, black paper and these ghosts disappeared.

CU
Tom
http://www.licha.de 49° 13' 54" N

September 20, 2002 01:29 PM Forum: CCD Imaging and Processing/Solar System

Best entry level scope for CCD Imaging??

Posted By Tom Licha

Hi John,

maybe you are interessted in that article about ccd and telescopes. With sortable comparison of the common CCD cameras...

http://www.licha.de/AstroWeb/articles_fullsize.php3?iHowTo=11

CU
Tom