I recently had an opportunity to compare a 6" refractor using a TMB 152/1200 lens cell with Anat's AstroPhysics 155 f/9 EDT at the Phu Hin Star Party in Thailand for four nights around the new moon in Dec 2009.
Anat and I have the two scopes mounted side-by-side on his Losmandy G11 mount and we did some casual visual tests. To minimise any other variables in the optical train, we use the same diagonals (AstroPhysics Maxbrights) and eyepieces (TMB Supermonocentrics, ZAO-IIs). And to maintain similar magnification, we use the Supermono 5mm on the TMB 152/1200 to get 240x and Supermono 6mm on the AP 155 EDT to get 233x. To improve the focusing on the TMB 152/1200, I added the Orion Helical Fine-Focusing Adaptor which does indeed help to achieve correct focus position for observations at high magnification. The AP 155 EDT is using a new FeatherTouch focuser.
Looking at the same target (Mars, Trapezium etc) each of us took a few minutes to compare them back and forth. Four other guys also took a look and said they did not see a difference. At first glance both scopes do indeed give the same excellent optical performance. Visually I observed only very minor differences: slightly brighter in the AP, slight warmer tone in the TMB (cooler tone in the AP), and better light control of veiling glare for off-the-edge-bright-object in the AP. These differences are very subtle, like splitting hair. The poorer light control in the TMB 152 is probably due to the Orion flex-shield used as dewshield for the TMB 152. The image crispness, resolution of planetary details, colour correction and the overall image contrast generally seemed to be the same in both scopes.
The seeing was quite good on most nights. On one occasion approaching dawn, I was able to observe Mars with clear and sharp details of both polar caps and Syrtis Major at 558x magnification through the AP 155 EDT with a Pentax XO 2.5mm eyepiece.
In spite of the presence of some thin high clouds on most nights, the sky transparency is still very good. My wife Siti had no problem counting 15 stars in the Pleiades at the zenith with her naked eyes using just direct vision. I only managed ten stars with direct vision and three more with averted vision, giving a total of 13 stars but this is still my personal best record.
Comparing AP 155 EDT with TMB 152/1200
Comparing AP 155 EDT with TMB 152/1200
Richard Low
Great picture. It is only when I can see a photo like this with some people as a size-perspective that I can appreciate just how big a 6 inch refractor is...wow!! very,very impressive.
Your photos on cloudynights are excellent also.The star party sounds great and you must have seen a lot of great scopes,as well as of course,your own.
Your photos on cloudynights are excellent also.The star party sounds great and you must have seen a lot of great scopes,as well as of course,your own.
Richard:
Nice review! Looking forward to your visit again
David:
You can see photos at the Phuhin Star Party from:
http://www.darasartonline.com/webboard/ ... p?GID=3571
http://www.darasartonline.com/webboard/ ... p?GID=3580
http://www.darasart.com/webboard/Question.asp?GID=3581
Some astrophotos from there:
http://www.darasartonline.com/webboard/ ... p?GID=3577
http://www.darasartonline.com/webboard/ ... p?GID=3578
If you have time, please join us.
Regards,
Anat
Nice review! Looking forward to your visit again
David:
You can see photos at the Phuhin Star Party from:
http://www.darasartonline.com/webboard/ ... p?GID=3571
http://www.darasartonline.com/webboard/ ... p?GID=3580
http://www.darasart.com/webboard/Question.asp?GID=3581
Some astrophotos from there:
http://www.darasartonline.com/webboard/ ... p?GID=3577
http://www.darasartonline.com/webboard/ ... p?GID=3578
If you have time, please join us.
Regards,
Anat
Anat,
thanks a lot for the links with photos,I enjoyed looking at them.
Would love to go to one of the star parties ,and even though I
am quite busy now,I will have to make a point of travelling to one of
the parties in the future,for sure.
A 6 inch Astrophysics is a real superstar of a telescope going on what I read on forums,and people are waiting as much as 10 years to receive a 130mm scope from this manufacturer......so what a great feeling it must be to have one of these fine American-made scopes in Thailand.
As the sum total of my astronomy equipment consists of Orion Resolux 15x70 Bino's and a Parallelogram, the equipment shown in the links is inspiring,and I look forward to maybe seeing and learning from some of these scopes before I decide what telescope to buy for myself.
Regards,
David.
thanks a lot for the links with photos,I enjoyed looking at them.
Would love to go to one of the star parties ,and even though I
am quite busy now,I will have to make a point of travelling to one of
the parties in the future,for sure.
A 6 inch Astrophysics is a real superstar of a telescope going on what I read on forums,and people are waiting as much as 10 years to receive a 130mm scope from this manufacturer......so what a great feeling it must be to have one of these fine American-made scopes in Thailand.
As the sum total of my astronomy equipment consists of Orion Resolux 15x70 Bino's and a Parallelogram, the equipment shown in the links is inspiring,and I look forward to maybe seeing and learning from some of these scopes before I decide what telescope to buy for myself.
Regards,
David.
- wucheeyiun
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nice ...
http://www.darasartonline.com/webboard/ ... p?GID=3577
BTW , Anat , cannot really read thai ... but is this shot ( horsehead nebula ) captured by dslr ( 450d ) and guided by toucam pro ... ?
http://www.darasartonline.com/webboard/ ... p?GID=3577
BTW , Anat , cannot really read thai ... but is this shot ( horsehead nebula ) captured by dslr ( 450d ) and guided by toucam pro ... ?
Yes. First 6 images were guided by the toucam pro and captured by the 450d hypermodded by myself. The CMOS is directly cooled by a peltier to reduce thermal noises. The detail of the hypermod is on my website.
http://www.dslrportal.com/hypermod.html
http://www.dslrportal.com/hypermod.html
Last edited by anat on Mon Jan 25, 2010 12:40 pm, edited 1 time in total.