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I have found my 12 inch Dark Star dob's main mirror. On the back it says FL 58.7" so 1490.98mm. Somewhere still to find is its original spider and flat in a holder. However that was for a 1.25 in focuser. For a 2 inch focuser to be fitted, what size flat do I need, and presumably holder assembly to go with it? The tube pipe is strong plastic with thickish walls. Is there a round hole cutting tool I could use to enlarge the existing one for a 2 inch focuser? Last requirement is a new cel, strong, light with easy collimation nuts etc. Orion's prices are high. Where else could I buy a new cel, spider and flat holder which have adjustable fixings to cater for different tube wall thickness. Then "Cap" can come out of the ice!
I am processing more of the data from the Deep Sky West Tak 106. This was collected in January 2017. Filters are 5nm Astrodons. Camera is a QSI 683. The Tak 106 is un-reduced. Data as follows: SII: 16 x 1800s Ha: 21 x 1800s OIII: 17 x 1800s For a total of 27 hours. It was put together using the SHO-AIP script in PixInsight. Then it was back and forth (several times) between PixInsight and Photoshop, trying to get something that looked OK. I also went back and forth on how much 'processing' I should do on this - I had more garish versions, but eventually settled on this one.
I did a quick (7 subs) image of the region around the Flaming Star Nebula and posted it... ... but I knew a few more subs would really help. I managed to get some over the last couple of nights. Both nights were a little murky but they were largely clear so I shouldn't complain.. This is a great region of the sky with loads of Ha objects, clusters, odd bits of nebulosity and so on and doing a slightly more widefield image allows me to capture more than one type of image at a time (value for money and all that!). Using a modified Canon 650D through a Borg 55FL f/3.6 scope and an IDAS HEUIBB filter, 30x 200 secs (guided) here's a reworked version as there's so many objects in there I thought I'd put an annotated copy in there two (manually - can't figure out the Pixinsight way to do it...). It's not perfect... there's artefacts in there caused by me stacking (and keeping) some subs that were taken at an angle to the rest..a practiced eye should be able to see that Actually, an unpractised eye probably can too I really must learn how to put pictures up here that don't get brutally jpeggerised... Oops - nearly forgot - does anyone know what the object at the top left is..? (The little red smudge...)
Hello all, New here, and normally not such a fan of internet fora, but this forum showed such promising content I decided to enroll and ask my question. Several years ago I bought a 10" Meade Newtonian as a project. I used it without motors or even controls, just moving it by hand. I decided to first improve the scope by getting rid of the idiotic plastic focuser. So I bought a proper machined solid aluminium Crayford, from an engineering point of view absolutely gorgeous item. I have not used the scope much since installing the new focuser, because I happened to move to a light polluted area. Now I am back in the relative dark, I want to use it, so I cleaned it all, reassembled and collimated (with a laser collimator), and started. First I noticed was that some of my eyepieces seem to be close to the end of the focuser movement, maybe due to the focuser needing some adjustment relative to the center of the OTA. Not a problem right now as all my eyepieces reach focal point. The troubling problem I did notice, is a blurred, but clearly visible image of the spider with secondary mirror. Mostly disturbing when viewing the moon, especially during daytime, as it increases contrast of course. At night I don't think it is that bad but I am wondering if I did something wrong with the positioning of the new focuser, the alignment or something else? I am of the opinion that my next improvement will be the spider, as this thing is very feeble. Maybe I will go for a guitar string design, but not sure yet any seasoned input on this is also appreciated. As comparison I have a Meade 6" as well, and this thing has the solid cast spider instead of the thin plates of my 10" (4mm thick vanes opposed to the 1mm) . The image in both is similar, which I did not expect. I thought my 10" would have to be much better and show less secondary spider image. So, there it is, do you peeps think this is normal or would I need to look at some stuff to conclude if something is wrong? Much appreciated, Kees
Was just thinking.. If the total diffraction depends upon the thickness of the spiders' vanes, then wouldn't it be a good idea to sharpen the spider? Bit like a double edged knife, all four or three vanes... any ideas or experiences with this?