M3

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  • Member since
    December, 2011
M3
Posted by Mares on Thursday, February 20, 2014 5:33 AM

The star cluster M3 from april 2013. Captured with  Omni XLT 150 mm refractor and Olympus E-510 DSLR. 20 x 30 sec. in DSS @ ISO 1600.

M3

Comments are welcome.

 

Regards Mares 

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www.runecb.com

Telescope: C9,25 XLT. Celestron Omni XLT 150 mm refractor. Sky Watcher HEQ5 Pro. Canon EOS 550D SLR, IS DBK 21-618, Baader Guidescope (10 x 60), Celestron Autoguider.

  • Member since
    March, 2008
Posted by Antitax on Thursday, February 20, 2014 10:28 AM

   The 150 Omni is an f/5 achromat, did you have to filter out chromatic spread, or is it tight enough at prime focus?

TS 8x40 Wildlife, 10x50 Marine/Fujinon 16x70/TS 80mm triplet, 6x30 finder, EQ-3 mount, TS 2" 99% diagonal/Celestron C5+ and 6x30 finder, DIY tripod/5" Bahtinov/12" GSO dob, 8x50 finder/Meade 2" 24mm 82°/Hyperion 24,13,10mm 68°/TS Expanse 17mm 70°/SW 7mm Panorama 82°/Ultima 2x barlow/Astronomik UHC-E filter/Baader O-III/Astro Solar 5" & 80mm filters/Sky Atlas 2000/Rükl's Moon Atlas/Canon 400D/5mW green laser

  • Member since
    December, 2011
Posted by Mares on Thursday, February 20, 2014 12:29 PM

Thats right, Antitax. My Omni XLT is an achromatic refractor. I did not use any kind of filter to reduce the chromatic spread, but a filter called Baader Fringe (against violet fringes) is on my list to buy. 

Regards Mares 

------------------------------------------------------------------------------------------------------

www.runecb.com

Telescope: C9,25 XLT. Celestron Omni XLT 150 mm refractor. Sky Watcher HEQ5 Pro. Canon EOS 550D SLR, IS DBK 21-618, Baader Guidescope (10 x 60), Celestron Autoguider.

  • Member since
    March, 2008
Posted by Antitax on Thursday, February 20, 2014 3:34 PM

   By the way, this 150mm f/5 achro is currently on sale at Teleskop Service; the scope and CG-4 mount combo can be had for 780€ instead of 989€.

http://www.teleskop-express.de/shop/product_info.php/info/p4009_Celestron-Omni-XLT-150R---150mm-Refraktor-Teleskop-on-CG4.html

   Very attractive deal since the optical tube only costs 749€.

http://www.teleskop-express.de/shop/product_info.php/info/p4010_Celestron-Omni-XLT-1590R-Gro-feld-Refraktor---Tubus-mit-Optik.html

   In Europe we have few places with little light pollution Sigh but we have Teleskop Service bargains. Bow

TS 8x40 Wildlife, 10x50 Marine/Fujinon 16x70/TS 80mm triplet, 6x30 finder, EQ-3 mount, TS 2" 99% diagonal/Celestron C5+ and 6x30 finder, DIY tripod/5" Bahtinov/12" GSO dob, 8x50 finder/Meade 2" 24mm 82°/Hyperion 24,13,10mm 68°/TS Expanse 17mm 70°/SW 7mm Panorama 82°/Ultima 2x barlow/Astronomik UHC-E filter/Baader O-III/Astro Solar 5" & 80mm filters/Sky Atlas 2000/Rükl's Moon Atlas/Canon 400D/5mW green laser

  • Member since
    December, 2011
Posted by Mares on Friday, February 21, 2014 4:33 AM

Yep, but whats the point ?

Regards Mares 

------------------------------------------------------------------------------------------------------

www.runecb.com

Telescope: C9,25 XLT. Celestron Omni XLT 150 mm refractor. Sky Watcher HEQ5 Pro. Canon EOS 550D SLR, IS DBK 21-618, Baader Guidescope (10 x 60), Celestron Autoguider.

  • Member since
    March, 2008
Posted by Antitax on Friday, February 21, 2014 10:33 AM

   The point is showing friends a bargain so they tell their friends until the info reaches someone who intends to buy one. The 120mm f/8.3 Sky-Watcher achromat is also on sale at Teleskop Service, I check these things regularly.

TS 8x40 Wildlife, 10x50 Marine/Fujinon 16x70/TS 80mm triplet, 6x30 finder, EQ-3 mount, TS 2" 99% diagonal/Celestron C5+ and 6x30 finder, DIY tripod/5" Bahtinov/12" GSO dob, 8x50 finder/Meade 2" 24mm 82°/Hyperion 24,13,10mm 68°/TS Expanse 17mm 70°/SW 7mm Panorama 82°/Ultima 2x barlow/Astronomik UHC-E filter/Baader O-III/Astro Solar 5" & 80mm filters/Sky Atlas 2000/Rükl's Moon Atlas/Canon 400D/5mW green laser

  • Member since
    December, 2011
Posted by Mares on Friday, February 21, 2014 11:58 AM

Do you work in Teleskop-Express and what is your opinion about the image ?

Regards Mares 

------------------------------------------------------------------------------------------------------

www.runecb.com

Telescope: C9,25 XLT. Celestron Omni XLT 150 mm refractor. Sky Watcher HEQ5 Pro. Canon EOS 550D SLR, IS DBK 21-618, Baader Guidescope (10 x 60), Celestron Autoguider.

  • Member since
    March, 2008
Posted by Antitax on Friday, February 21, 2014 3:13 PM

Mares

Do you work in Teleskop-Express and what is your opinion about the image ?

   The work I do for Teleskop-Express is buying stuff from them every few months. The image? I'll answer for one item at a time. The 17mm 70° Expanse eyepiece (clone of Astro-Tech's AF) is a bit sharper than the Hyperions at the center. Jupiter in the Expanse is "dryer", a bit more clean-cut.

    I never spotted a difference in daytime testing but it showed by night with the large dob. Edge sharpness is excellent but only after you learn to put your eye at the precise center and at the right distance, this is critical with this glass or stars stretch wildly.

   My TS 10x50 Marine is a clone of Orion's Resolux and an Oberwerk model with the exact same look, reviews of these are reviews of the Marine.

   The 8x40 Wildlife is nearly as sharp as the Marine over the whole field, and very transparent with no flares, ghosting, vigneting, or any other issue.

   Then my 80mm triplet, which I compared with a friend's Tele Vue 101. An artificial star, real stars and colorful dying autumn foliage were the targets. There's a caveat however, a triplet is optimized to provide maximal sharpness and contrast at the center (where you put planets), but needs a corrector for full-field photography because edge sharpness is less rigorous.

   On the other hand, a 101 is a compromise between keeping good star roundness at the center and acceptable star roundness all over the field, with no need for an extra flattener (the flattener is already inside). Keeping this in mind, the apparently unfair comparison, 80mm vs 101mm and 646€ vs 4,100€, 3 lenses vs 4, will make more sense. Made in Asia pricing vs Made in USA pricing, obviously.

   The 80 cuts through turbulence where the 101 submits to it often; the 80 has almost all its resolution all the time but the 101 needs calmer air to show its edge. Contrast is a tiny bit better in the triplet, but the difference won't make someone regret buying the Tele Vue, because as a stand-alone astrograph, it does its job very well, except for vigneting that some can ignore while some others can't, matter of personal choice.

   Orion's carbon-tube 80 triplet and Levenhuk's triplet 80 are clones of mine. So is Astro-Professional's 80mm carbon triplet; both have a Strehl ratio (optical quality ratio) between 0.95 and 0.99 depending on the colors tested. It doesn't get any better, not even with high-end russian LZOS lenses or Takahashi lenses.

http://www.astro-foren.de/showthread.php?12618-APO-Triplet-80-480-eineiige-Zwillinge

  

TS 8x40 Wildlife, 10x50 Marine/Fujinon 16x70/TS 80mm triplet, 6x30 finder, EQ-3 mount, TS 2" 99% diagonal/Celestron C5+ and 6x30 finder, DIY tripod/5" Bahtinov/12" GSO dob, 8x50 finder/Meade 2" 24mm 82°/Hyperion 24,13,10mm 68°/TS Expanse 17mm 70°/SW 7mm Panorama 82°/Ultima 2x barlow/Astronomik UHC-E filter/Baader O-III/Astro Solar 5" & 80mm filters/Sky Atlas 2000/Rükl's Moon Atlas/Canon 400D/5mW green laser

  • Member since
    November, 2009
Posted by Poppa Chris on Friday, February 21, 2014 3:38 PM

Antitax, I think Mares was speaking of an opinion of his M3 image.  I found it to be very pleasing for the equipment used.  With a more critical eye at first, I felt it lacked a bit of resolution.  But when I read about the equipment used to take the photo I relaxed my critique a bit and feel that is a fine image.  If I could add one thought: Like any image taken with any equipment the three "F"s of astrophotography must be kept in mind; Focus - Focus - Focus (After that, focus some more).

---Poppa Chris---

Denham Springs, Louisiana USA

"Second star to the right - Then straight on until morning!" - Peter Pan

Celestron CPC1100GPS (XLT) - 279mm aperature, 2800mm Focal length. (f10) Celestron Ultima LX (70deg AFOV) Eyepieces 32mm thru 5mm, Canon EOS Rebel T2i DSLR, Backyard EOS imaging software, Orion Star Shoot Planetary Imager IV, Celestron Skymaster 15x70 binoculars

 

  • Member since
    March, 2008
Posted by Antitax on Friday, February 21, 2014 6:14 PM

   Yes, he meant that image, not the image through TS optics, I got carried away by the discussion about TS. That's fine because these things had to be said, anyway. The M3 pic is very good for an unfiltered achromat, it would be a bit better at ISO 400. ISO 800 and 1600 make the pixel frame more visible, and ISO ratings are not linear.

   In theory 800 is twice as fast as 400, and 1600 is supposed to be twice as fast as 800 but in practice that's true only in daytime photo. In astrophoto the ISO proportions break down over long exposures; not knowing this, many imagers set their cameras at the highest ISO values hoping to work faster but this turns the image grainier.

   Try the same exposure time with lesser ISO values and see how the picture sharpens and cleans up, without dimming much. If you take longer exposures tracking error could show a bit, that's a risk. However grain will show for sure with extreme ISO ratings, that's a certainty. People need to experiment more, in other words, disobey the rules and challenge common wisdom to gain their own experience.

TS 8x40 Wildlife, 10x50 Marine/Fujinon 16x70/TS 80mm triplet, 6x30 finder, EQ-3 mount, TS 2" 99% diagonal/Celestron C5+ and 6x30 finder, DIY tripod/5" Bahtinov/12" GSO dob, 8x50 finder/Meade 2" 24mm 82°/Hyperion 24,13,10mm 68°/TS Expanse 17mm 70°/SW 7mm Panorama 82°/Ultima 2x barlow/Astronomik UHC-E filter/Baader O-III/Astro Solar 5" & 80mm filters/Sky Atlas 2000/Rükl's Moon Atlas/Canon 400D/5mW green laser

  • Member since
    December, 2011
Posted by Mares on Saturday, February 22, 2014 5:28 AM

Hi Antitax,

It was interesting to read that you are working in TS, because i`m a customer in Teleskop-Express. Wide selection of equipment and excellent service. Its always a pleasure to buy astro-equipment here.

Thank you for the comments about the image. :) Its probably better to use a lower ISO value than my 1600, so next time i will try to use ISO 800 and a filter. I know ED APO (and Quad) refractors are better to use on DSO`s, but these scopes are expensive compared with my Omni XLT. My next scope will probably be an ED Apo (100/120 mm).

Poppa Chris: Yep, i think the image has some lack of resolution too, but this is mainly from the processing in PaintShop Pro X4.  A more careful treatment of the image would done the final result better. Thank you for the comments anyway.

 

Regards Mares 

------------------------------------------------------------------------------------------------------

www.runecb.com

Telescope: C9,25 XLT. Celestron Omni XLT 150 mm refractor. Sky Watcher HEQ5 Pro. Canon EOS 550D SLR, IS DBK 21-618, Baader Guidescope (10 x 60), Celestron Autoguider.

  • Member since
    March, 2008
Posted by Antitax on Saturday, February 22, 2014 1:42 PM

Mares

ED APO (and Quad) refractors are better to use on DSO`s, but these scopes are expensive compared with my Omni XLT. My next scope will probably be an ED Apo (100/120 mm).

   Have you noticed this one?

http://www.teleskop-express.de/shop/product_info.php/info/p6728_Meade-102mm-f-7-Triplet-ED-APO---Optik-mit-Tubus.html

   If they give you the customary rebate you might have it for 860€ or a bit less, but even at 899€ it's a steal. No one else offers a 4-inch triplet for that kind of sum. (When I said I work for them I wasn't serious but no problem).

TS 8x40 Wildlife, 10x50 Marine/Fujinon 16x70/TS 80mm triplet, 6x30 finder, EQ-3 mount, TS 2" 99% diagonal/Celestron C5+ and 6x30 finder, DIY tripod/5" Bahtinov/12" GSO dob, 8x50 finder/Meade 2" 24mm 82°/Hyperion 24,13,10mm 68°/TS Expanse 17mm 70°/SW 7mm Panorama 82°/Ultima 2x barlow/Astronomik UHC-E filter/Baader O-III/Astro Solar 5" & 80mm filters/Sky Atlas 2000/Rükl's Moon Atlas/Canon 400D/5mW green laser

  • Member since
    December, 2011
Posted by Mares on Sunday, February 23, 2014 8:12 AM

Thank you for the advice. The scope looks ok, but i`ve not deceided to buy anything yet.

Regards Mares 

------------------------------------------------------------------------------------------------------

www.runecb.com

Telescope: C9,25 XLT. Celestron Omni XLT 150 mm refractor. Sky Watcher HEQ5 Pro. Canon EOS 550D SLR, IS DBK 21-618, Baader Guidescope (10 x 60), Celestron Autoguider.

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