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ribuck

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ribuck last won the day on May 3

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  1. Paul - It looks like you were spot on with your analysis, as i've had a similar comment on Cloudynights, where i was told that this is perfectly normal behaviour when way out of focus with this coma corrector. So just like you mentioned, it's just due to the critical nature of the F4 system & coma corrector. So all is well, as it was not an actual issue, simply a lack of knowledge on my part. So I can sit back and relax now and stop chasing my tail over nothing. Cheers, Rich.
  2. If anyone else has anything to add, then please feel free to comments as i would really appreciate as much input as possible.
  3. Hi Paul thanks for the feedback - Having never imaged with a fast newt before i wasn't sure if this was normal or not when viewing stars out of focus. For the clipping on the right is easy to fix as i have the primary racked in tight against the primary springs - i can easily loosen them off to push the the mirror a good 10mm up the tube. In terms of the general results, things generally look ok - just ignore the star shapes as the scope was way out of collimation when it was taken. The out of focus star tests were done later after i had recollimated.
  4. Hi All, Towards the end of last season i bought a 10" Quattro and associated Sky watcher Aplanatic coma corrector and i've really struggled to understand what i'm seeing when i defocus the stars. Basically the stars closer to the edge have severe light drop off in a curved fashion - but if you look at the curved light drop off - it follows a pattern almost like a circular patterns when you look at the stars in each corner. My coma corrector is spaced at exactly 55mm - which is the correct spacing for the skyatcher apalantic coma corrector. Collimation wise, everything should be ok as i collimated it with a Howie Glatter Laser and Cats eye Kit so it should be pretty darn close. I think the secondary mirror rotation also looks ok as the secondary looks like a perfect circle in the 2" sight tube. Any advice would be greatly appreciated as i really dont know what i'm seeing. Thanks in advance, Cheers Rich.
  5. Many thanks all for the kind comments.
  6. i guess it comes down to personal preference, budget and many other factors
  7. Marmot My rule of thumb is as follows :- Refractor Imaging Broadband Imaging(LRGB) = Triplet, as doublets focus the RGB light differently which require extra post processing to get the colour balance sorted. Narrowband(Ha, SII, OIII) - Doublet or triple are both fine. Achromat = Never Planetary Imaging - Recommend Triplet Visual In most cases a doublet will be just fine and in some cases more preferable than a Triplet. Most modern doublets have very little CA and in a lot of cases it's barely noticeable. Achromats = No, no, no
  8. ribuck

    Mars compilation 2020

    Simply Stunning Andy. I've long thought about trying my hand at planetary imaging. Now how do i sneak a C11 past my wife without her noticing.
  9. Gabs an 80mm Refractor is a very good starting point, as it will be easy to guide and balance on your mount. For imaging with Refractors be aware there are several different types :- Achromatic (No good for imaging) doublet (Semi-Apo) - these are fine, but require more time to process images due to colour imbalance Triplet (Apo) - ideal perfect choice as they have no colour imbalance. Ideally if you can buy a triplet, then that would be the best option, but it comes down to cash. You will also need a Flattener or you will get elongated stars at the edge of your images. And finally as other have said you need to think about your mount - Starting out an EQ5 class mount will be great, but think longer term as if you want to get bigger scopes in the future this will not be ideal, so buy the best you can afford. Now onto the guiding - for short refractor you dont need worry as much and, but you will need a guide scope - something small like a 50mm guide scope will be great and of course a guide camera. I recommend getting a camera suited for planetary imaging as they make great guide camera and at a later date you can use them to image the planets. Out of interest - what are your intended targets for imaging ?
  10. Hi Gabs, May i offer some advice from a person who has tried imaging with just about every scope type possible on the planet. Newtonians aren't ideal as first imaging scopes, they require a lot of precise collimation and cheap mass produced newt's are not ideal as their mirrors can move a lot due to poor build quality / design. When starting out in astro Imaging you need something small, light and with a short focal length, such as 80mm-100mm Refractor as they are pretty much plug and play and you dont need to worry about back focus and are far easier to guide. Imaging with any type of reflector tends to be a lot more difficult / complex that using a refractor, and with that comes an awful lot more frustration and pain. With a newt, if you are lucky you will spend 50% of your time fighting it and 50% imaging and with a refractor - it's 95% imaging and 5% problems. These frustrations also apply to other reflectors such as SCT's, RC's etc. There are a whole bunch of other reason, but i wont bore you with them, but trust me when i suggest you start with a small refractor. With astroImaging also keep in mind it's a whole different level of investment, as you suddenly need a much better mount which tracks well, you need a camera and filters depending on which route you go, then you'll need Focal Reducers or coma corrects, then you need to upgrade focusers in most case with the exception of small fracs, then you will want to motorize your focuser -it get real expensive really quickly. Rich.
  11. If nothing else - just replace the rubber to get proper spring to help hold collimation as the scope moves across the sky.
  12. god yes get rid of the rubber and get as set of good springs - dont buy astro ones as they are a rip off as they charge £20 for 3 little springs. i learnt that that the hard way. Typically they then tend to have about 15-20mm height and tend to made from thicker 1.3mm wire. something like this. Teleskop-Express: TS Optics reinforced springs for main mirror cell - set of three As for the primary mirror mask - it's essentially a flat ring that fits above your primary mirror to conceal the edge of your mirror that refracts light. it has 2 purposes It softens and helps reduce diffraction spikes on bright stars. it drastically reduces the halo effect often found on bright stars. Ig you look at my M81, there are zero halo's around the stars the internal halo around cores of the star are greatly reduced and smoothed - just ignore the dodgy cores of my stars as they are over saturated and need sorting.
  13. 3 upgrades i recommend for anyone with a newt :- Focuser Primary Mirror Mask Primary Mirror cell spring upgrade
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