Archive for September, 2009

Planetary astrophotography set up – Jupiter opposition August 2009

I would like to present the astrophotography set up I used for the recent pictures of Jupiter I took during the Jupiter Opposition of August 2009. I found this set up to work quite well, allowing me to take quickly, and in a repeatable manner high resolution pictures (when the seeing allows it!).

This set up will work on any Telescope having enough in-focus travel, which is the case for Schmidt Cassegrain and Maksutov Cassegrain Telescopes.

Telescope and accessories

First, the Telescope: Orion Maksutov Cassegrain 7″ – on an Orion Atlas Mount attached to a Pier.

I am very happy with this telescope. The scope has to be placed outside 2h before observing to cool down, but otherwise the scope is very easy to set up, keep extremely well its collimation, and has a quite a good optical quality. I noticed also that once the tube reaches thermic equilibrium, the scope is less affected by Turbulence (most of the time) than my larger aperture telescope (SCT 9.25″) when the seeing is average or below average (3-4/10 on ALPO scale) – which is unfortunately the case most of the time at my location (San Bruno, CA).

Here are the accessories / cameras I use for this set up:

  • 1 – Telrad unit, with Dew heater: the Telrad is very convenient to align the Telescope and/or point to bright objects. There is no need for a conventional Finder when doing planetary observation with a go-to scope! Note the Telrad gets foggy very quickly – the Dew heater is a must as soon as the temperature drops below the dew point. The dew heater was ordered at Agena AstroProducts
  • 2 – Focusing knob: It is probably not as good as an electronic focuser, but it is cheap and does reasonably well the job. The focusing knob was ordered at ScopeStuff
  • 3 – Orion Filter Wheel: a must to take RGB pictures, especially with a planet like Jupiter, having a very fast rotation.  RGB pictures have to be taken within 3 to 4 minutes maximum with this Telescope, otherwise the effect of rotation is noticeable when integrating RGB channels.
  • 4 – Flip Mirror: with this it is extremely convenient to center planets especially with a planetary Camera having usually quite small sensor sizes. The flip mirror was ordered at Orion.
  • 5  – Imaging Source Camera  DKF 21AU04.AS: this is a great B&W camera with a sensitive and high resolution chip. Maximum frame capture is 60 fps!  The chip sensor is very small (1/4″)  but it does not matter for high resolution planetary astrophotography. However the camera cannot really be used to capture large lunar landscapes, and the Flip mirror helps saving time to center the planet in the sensor field of view.
  • 6 – NetBook Asus 2G Ram/160G Disk : even though the camera capture frames at high rate, since the resolution is 640×480 on 8 bits – the size of the AVI files for a 30-40sec movie is still small (compared to my Orion  Solar System Imager Camera where the Asus had trouble handling the frame download rate). The Netbook is built like a Tank which is great on the field  – and has a long battery life (+6 hours).

Planetary_setup_09012009

Being new to B&W CCD astrophotography, I found the following benefits for planetary photography compared to Color CMOS sensor such as the Orion Solar system imager III:

  • b&w camera are usually more sensitive, minimizing the exposition time (even with RGB filters, compared to CMOS color cameras)
  • taking exposures in each channel allow an optimal focus for R/G/B – quite useful especially when captured objects are low on the horizon, with extra color dispersion caused by the athmosphere
  • There is no bayer matrix in front of the sensor – for the same sensor pixel resolution, black and white sensor with RGB capture will produce more detailed images
  • No bayer matrix and IR filter in front of the sensor gives complete control / more options when choosing which combination of filters to use

On the cons side, taking RGB pictures takes extra captures that have to be done in limited time (at least for Jupiter) and some extra processing time, but this is far out weighted by the benefits…

Image Processing

In terms of AVI/ picture processing I use the following software:

  • Registax V5 for making composite images for each RGB channel.
  • Max DSLR for aligning and combining RGB channels
  • Occasionally, Astra Image 3.0SI for their great deconvolution utility
  • PaintShop pro photo X2 for final processing:  image rotation, cropping, histogram adjustment, and color adustments. PaintShop pro does the job and is less expensive than PhotoShop.

Voila !

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Jupiter Opposition – 25th of August 2009

The seeing was bad  this day (3/10) but the Great Red Spot, Io’s disk and its shadow were visible.

It seems to me the seeing was better in Early August, when Jupiter was culminating early in the morning …

Location: San Bruno, CA – Telescope: Orion Maksutov Cassegrain 7″ with Atlas Mount

CCD Camera Imaging Source DKF 21AU04.AS with RGB color wheel

Picture at Focal Plane F/D 15. All pictures are processed with Registax,  Maxim DSLR, and Paintshop Pro

08/25/2009- Jupiter- 1327 frames at 23:22 PM PDT

08/25/2009- 1436fr - 23:1408/25/2009- 1385 frames - 23:30PDT08/25/2009 - 1990 frames - 23:36PDT

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New Orion Maksutov-Newton 190mm and artificial star testing…

My recent scope acquisition: an Orion Maksutov Newton 190mm…  I bought a  “bundle” (brand new Atlas mount and showroom Mak Newt)  in July 2009 .

I tested the telescope with an Astrozap artificial star, following the procedures documented in the book “Star Testing” from H.R. Suiter.

I would recommend anybody buying a telescope to make this investment (artificial star and the book) and go through this procedure. It is worth it. A couple of month ago, I had to return a first Maksutov-Cassegrain because of some optical issues that was somewhat revealed looking a stars (but was not sure if it was due to turbulence or not) and the defect was revealed very clearly with the artificial star testing. I got a new scope because I was in the 30 days return policy – and the new scope was as good as the Mak-Cassegrain optical design permits…

Waiting for a great seeing to do a “real” star testing may not happen during the 30 days return policy. Make sure that when you do artificial star testing you have plenty of space  – otherwise you introduce aberration that would not happen with “real” stars. In my case I placed the artificial star at least at 200 yards from the telescope.

To come back to my new Maksutov-Newton – I made the test and found (after thorough collimation) the optics extremely satisfactory, with nice diffraction patters in focus, and very similar (almost textbook-like) forward and inward out of focus diffraction patterns.  Visual image of Jupiter was also crisp and contrasty, making it a good planetary instrument when well collimated, even though this is not the primary purpose of this scope (which is flat field astrophotography).

Look at the Perseus double cluster picture taken with the Mak Newton. Stars are pinpoint even at the edge of the picture (Canon EOS full frame). You would not have the same picture with a Newtonian (except if using a coma corrector) or even a regular Schmidt Cassegrain telescope.

This shot of M13 was taken with the Mak-Newt and my Qhy9 Black and White camera.

This shot of NGC 981 on this page was taken using the Mak Newton with my Canon XTi and an Orion Skyglow filter.

Maksutov_newton_08082009_3Maksutov_newton_08082009_9

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Pier and Atlas Mount

I installed (august 2009)  a brand new Pier that I can use with my two mounts (new Orion Atlas and Orion Sirius).

The new Atlas Mount (bought in July 2009)  is a must with heavier equipment I have now: Maksutov-Newton or Celestron 9.25″ SCT equipped with guide scope and camera. The overall assembly is far more stable than the mount and tripod and should lead to much better quality tracking and photography.

The pier was bought at Skyshed. I would recommend this company – it went pretty well and it was fairly easy to contact them to check from time to time how things were progressing.

I ordered two adapters / plate – one for each mount. A 45″ x 14″ hole was dug and filled with concrete and four 1/2″ J-Bolts are used to support the Pier.

The ordering took about 2-3 weeks. Below picture of the assembled pier with the Atlas mount plate adapter and Maksutov-Newton 190mm. I am very happy with the result!

IMG_0968

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Jupiter Opposition – 9th of August 2009

Some more pictures with the Imaging source camera – San Bruno, CA.

Seeing was not great 3-4/10 ALPO scale.

Telescope: Orion Maksutov Cassegrain 7″ with Atlas Mount

CCD Camera Imaging Source DKF 21AU04.AS with RGB color wheel

Picture at Focal Plane F/D 15. All pictures are processed with Registax,  Maxim DSLR, and Paintshop Pro

Jupiter on 8/9/2009 at 11.43pm PDT – Seeing 3-4 / 10 on ALPO scale- Stack of 539 R / 349 G / 763 B frames

08/21/2009 - 11:43pm

08/22/2009 - 00:34am08/22/2009 - 00:43am08/22/2009 -  01:58am

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