James4

Hey Isabelle, I was trying to compare your image with Stellarium and the order in your photo (just because of our line of site) is Calysto above Europa on the left - then Io closest on the right (which swung in quite quickly), then Ganymede. I need to fix my blog - the image size has thrown it into super wide mode - Yikes!

This blog is part observation, part scope comparison, and part equipment test. What can I say my time is limited I had to squeeze it all in to one session :) All-nighter Friday night started poorly - I missed the boat home (I was the last car not to get on). I left work at 4.15pm and finally got home at 9.15pm. So I thought, I'm not losing my Friday night. I decided to pull an all-nighter and finally get Jupiter under a clear sky. I had dinner, took a shower and delayed until Jupiter was high enough. I setup up at 1.00 am. Refractor first Jupiter was now well up and looked steady to the naked eye. I setup my Celestron CG5-ASGT and Put The Explore Scientific 152mm (Achro') Refractor on the Mount. Jupiter looked nice at 121x so I pushed up to 197x. One of the moons was closing towards Jupiter but I was too busy looking for detail on Jupiter's cloud decks to think ahead. After 30 minutes or so, I realised the close in moon had disappeared and its shadow was now transiting Jupiter. I studied the shadow and shortly after it began, I noticed a dark feature in the North Equatorial Belt - I thought it was a double shadow transit. Astro-Tech 8" Reflector I took the Refractor off the mount and switched to the 8" reflector - I wanted to find which was sharper. I used the same eyepieces on both scopes - a Celestron Ultima LX 5mm 2" - with Antares 1.6x Barlow 2". This gave me 256x on the Astro-Tech and 317x on the Refractor - a significant difference but Jupiter did not offer any less detail down at 200x. First look and surprisingly I could not see the shadow with the 8". Jupiter was steady but show low contrast in both scopes - I think high haze was responible as the stars were dim. I moved the focuser back and forth back and forth trying to pull in that dark feature I knew was there - but I could not see it. This scope has really good optics - I have seen a perfect diffraction ring pattern around bright stars at high power - and for imaging it is superb. But the oversize secondary (wonderful for photography) is 35% by area and that's enough to reduce contrast visually. Fringe Killer I switched back to the Refractor and again the shadow transit was visible - I shot lots of video with a pocket digital and snapped many stills with a Nikon DSLR at Prime plus Barlow. The big Achro' was throwing up a strong purple halo around Jupiter - bigger and purpler (is that legal) at 317x than at lower power. I added a Baader Fringe Killer. If I trust any company to know what they are doing, its Baader. The fringe was reduced and now appeared more crimson than purple but the view was no sharper than before. It was only the second time I had seen Jupiter all year and the first time seeing it high up in the sky. I was a little underwhelmed at how low contrast the view was - I have seen a shadow transit more obvious in a 4" Refractor. But it was great to be under the stars and have an unexpected shadow transit of Io for a scope comparison. Summary The Refractor - despite the fringing was able to show more detail. Jupiter appeared as though I was looking through haze - so I have no doubt under transparent skies the Astro-Tech would also have shown the transit. The Fringe Killer - not effective is all I can say - perhaps the haze reduced its effect? I still want to have the option of using it though - perhaps it will prove itself as I use it more. Feel like a got my Friday night back - thanks Jupiter!

Great blog Isabelle! Love the picture of your dinner as well as the ones of The Moon and Jupiter - very inspiring to get out and see stuff! I was looking at Jupiter too Friday night and into Saturday 4.00 am - I'm thinking the moon on the inside right is Io because I watched it cross in front of Jupiter around 2.00 am Saturday - I'm just about to blog it. Not been to the lounge for ages ... Thanks for the inspiring report. James

Brilliant Blog Isabelle. I dream of one day being loaded (in the financial sense) enough to visit all of the world's great observatories. Flagstaff and Kit-Peak will be the first two! Hope your eyes get back to normal soon - I'm sure we are all due some clear skies soon.

Just wanted to post some information on using the Baader (multi purpose) Coma Corrector on my F4 Astro-Tech 8" Newtonian. I've been hearing (from telescope dealers themselves) that some coma correctors do a very poor job of correcting coma in fast Newtonians. Some also increse the focal length and therefore the F Number. For those of us that don't guide, the F Number is king. I don't want to lose the edge that F4 gives me. For this reason I chose the Baader Coma Corrector, as it specifically states it does not increase focal ratio. Image 1 is the corner of an image of M31 taken with my F/4 Newtonian without any correction. Image 1 This is the bottom right corner of an image of Andromeda You can see the stars around M32 are blurred and enlarged. Image 2 is a later image of Andromeda with the Coma Corrector in place. Image 2 This is a similar region of a later image of Andromeda. This was taken with the same equipment as the first photo - but with the coma corrector attached to the DSLR In Image 2 with the coma corrector in place, not only are the stars in the corner of the frame fully corrected, but some stars are visible in the cloud of M32 which are invisible in the first image. The difference in orientation is due only to the DSLR being oriented differently on the telescope and not to any change in focal length. This coma corrector can be fitted to eyepieces with additional T2 rings. I'm not concerned with this, my requirement is that images are corrected for photography. I therefore leave the corrector attached to my camera's T-ring. I simply fit this assembly to the camera for imaging. I bought this corrector new for $149 USD. A good deal in my opinion. Thanks for reading.

Hey Matt, no worries. I didn't realize the LX10 was not GoTo. I agree on trying new scopes, I change to something new on average about every 2 years. I usually sell the used gear for more than 50% of its cost, so it doesn't cost me a fortune to move on. Good Luck

CG5 All Star Software Polar Alignment I have always used a Polar Scope to set up equatorial mounts for imaging. When I heard about Software Assisted Polar Alignment I was skeptical. I was skeptical because during star alignment I have often found alignment stars to be fairly off centre and occasionally outside the field of view. However this was happening with my C8 partly due to having to rotate the 2" Diagonal every time the OTA moved to a new star. When I rotated the Diagonal, the star would shift noticeably in the Field Of View. After upgrading my Hand Controller to Version 4.16, I decided to give the new All-Star Polar Alignment a try. I performed a 2 star alignment with 1 Calibration star. The stars were Sirius, Procyon, Rigel. Procyon was the calibration star and I was pointed at Procyon when I initiated the Polar Align Routine. The routine is now accessed by pressing The Align Button on the hand controller. The hand controller prompted me to centre Procyon in the eyepiece then press Align. I did and the scope then re slewed to Procyon. But this second slew moved the scope to where Procyon should be if the mount were accurately polar aligned. Now I moved the scope back to Procyon by using only the Altitude and Azimuth adjustment knobs on the mount. Its best if you put the hand controller down during this phase - the temptation is too great to tap the direction buttons as you normally do when aligning on stars. I had initially used the polar scope to put Polaris in the centre of the Polar Scope. This way I knew my alignment was already close so there should not be any large correction required. When the scope re slewed to Procyon, it was off target by at least as much as two moon widths. I scoffed at this and thought the calculation must be way off. But I thought I would complete the test anyway. I gradually moved the scope back on to Procyon using the mount adjustment knobs. This took around 5 minutes. I took off the Polar Scope cover and looked for Polaris. I did not expect to find it in the field of view. But in fact it was positioned just outside the small circle for Polaris in the Polar Scope. I was surprised at this mainly because it seemed I had moved the telescope a lot to align on Procyon. I looked at the orientation of Cassiopeia in the sky and compared with the Polar Scope and realized if I rotated the mount to match the sky view - Polaris would indeed be inside the small circle. From this I realized the Polar Scope has a much wider field of view than I expected. This means in turn that any error in placing polaris using the Polar Scope is much larger than it appears. The opposite is also true, that the main scope has a much narrower field and therefore potentially a much higher accuracy in placing Polaris. I did then take some images and found tracking to be good. My timer had a low power malfunction and set all my exposures to 30 sec instead of the 60 sec I had programmed. I was therefore not able to compare directly with previous longer image runs. Out of 40 images though, 38 were un trailed at 800mm and 30 seconds. This test has caused me to reverse my opinion on this one. I had been confident the Polar Scope would be more accurate. But now having seen how wide the FOV is in the Polar Scope it should be possible to easily improve on this by carefully using the SW Polar Alignment.

Hey Matt, I'm puzzled as to why you sold the LX10 SCT and would still consider the Nexstar 8SE. Outside of that I would note that for photograhy, you really don't need aperture, instead you need speed - a fast focal ratio - e.g. F4 is very fast, F6 is average. Also if you keep your focal length below 1,000 mm your tracking will be much easier. However on the visual side, big aperture is required to see DSO. In the long run most people have one rig for Astrophotography and one for visual. I note that your 10 years with the LX 10 gives you considerably more astro experience than me - but I don't mind giving you my objective opinion. Good luck and have fun.

Hey Tod, how are you finding the double star atlas? I'm thinking I should pick one up soon too. Just be using magazine articles from Sky&Telescope so far. James

-19C Isabelle, and I thought it was chilly at -1C. We are sure spoiled here in BC. Enjoyed your blog - will need to read the others now too!

I'd just like to point out that Stargazers Lounge is solely responsible for me deciding last week, after 5 years of ignoring 'Stars' and treating them like sign-posts to everything else, that wait a minute, there may be something interesting about them after all. The thread on Sirius B - soon launched me out the door onto the driveway to have a look for the impossibly tricky double that is Sirius and Sirius B. Here's what happened: I setup my 8" Astro-Tech AT8In on CG5 ASGT Mount on the driveway. This is an F/4 scope and so certainly is not the ideal tool for double star splitting. Probably the 8" SCT with its longer focla length would make sense. But the AT8IN is 'the new scope on the block' and wowed me with its light gathering abilites compared with the C8, so I decided to try it out. I began by slewing to Rigel which also has a close companion, with almost the same separation as Sirius from Sirius B. However, Rigel and its companion are not as widely separated in magnitude and this is a much easier double to observe. I had a couple of other goals tonight. One was to try the CG5's Software Polar Alignment for the first time. Up until now, I've always used a polar scope. I also wanted to test the Baader Coma Corrector for the 8" Newtonian. I did a 2 star alignment followed by 2 calibration stars, then selected 'Polar Align' from the menu (my version of the Hand Controller was 4.13). Half way through my second star aligment the power failed! I restarted and decided to pick 'last alignment'. This worked find and I slewed to Rigel. I found the Rigel pair fairly easy to split after a few minutes. But it could be missed if you are not aware it has a companion star. As I aligned the scope I checked for doubles on a few other stars - noting Polaris' quite faint companion well separated from it. Sirius was now approaching the Meridian (the East/West border) due South and so was moving towards its highest and best position for observation. Even so it would not climb above about 35 degrees in altitude. I used a 4.3mm W70 Antares eyepiece for 186x on my 800mm FL 8" Newtonian - this worked well for Rigel. For Sirius I doubled this up to 372x. Sirius at first sparkled then later was a little muted by the thin cloud that was affecting its appearance on and off. I was not seeing Sirius B and had intentionally not looked up its position so as not to cloud my judgement on detecting it. About 40 minutes into observing, for just a few seconds, a fleck of light persisted very close to Sirius. I moved my eye position around to try to confirm it. But after about only 5 seconds it was gone. There were numerous annoying reflections in the eyepiece which had to be discounted. I cannot blame the eyepiece for this, as a very bright street light bores almost directly down the scope tube when I'm looking South. Despite an OTA that extends well in front of the focuser and a 2 foot long Dew Shield, the light still spills well into the scope tube. The CG5 had tracked Sirius well past the meridian and the motor housings were close to touching. I broke off the pursuit for now. I attached the camera - a Nikon D5000 - and took a few test images of The Pleiades to check for star quality. I then went back, first to Rigel and then Sirius, to see if I could pick up the elusive Sirius B on my DSLR. After that I took another 20 minutes using 372x (a 4.3mm eyepiece with 2x Barlow) on Sirius to try to split its companion. I made a drawing of the position of another possible candidate that seemed to be flitting in and out of view just above a diffraction spike, but later after working out its position angle, I ruled it out. Below: Rigel with its companion hiding in the lower diffraction spike. About 20 minutes earlier it was easier to see visually because of cloud movement. Below: Sirius and Yes, Sirius B, at the 10 O'clock position. The white halo is a result of thin high cloud which kept chaing the appearance of Sirius during observation. Below: Sirius and Sirius B (again at 10 O'clock). I confirmed the star field and Sirius B's position with an image from Tuscon-Skies. These images were all taken at prime focus (800mm FL) with a Nikon D5000 DSLR - exposure on Sirius was 10 seconds at ISO 3200. An enjoyable challenge. Although I did not see Sirius B visually, I was pleased to photograph the elusive 'Pup' as its called. Also having knowlege of its appearance I think will make it just a shade easier to detect visually under more transparent skies. A good 2 1/2 hours under the starry skies instead of in front of the TV! The crescent Moon and some high thin cloud were lighting up the sky. On the ground I had a Victorian 'full radiation' street light, and several unshielded neigbhours lights bearing down on me. The best defense turned out to be a fur hood! I flipped this over my head and the eyepiece while observing. Above: Orion, Taurus and The Pleiades above the scope. Sirius is above the EZ Finder to the left. It was -1 C and ice formed on the scope and camera gear. I look forward to trying again for a visual observation of Sirius B when the skies are more transparent! The SW Polar Alignment was fine for visual, but not good enough for photograhy. To be fair I did not take much time over it. Adding more alignment stars should improve its accuracy. I will try it again to decide if I can beat the accuracy of aligning with the polar scope. I would sure welcome not having to crawl around on the ground under the polar scope. Its well worth perfecting so I will try a few ideas on refining it. The Baader Coma Corrector - not sure as there was drifting on my images. But the star shapes are nice and round. I will also have to try this again to decide if the image has improved. Clear skies!