Stefan73

Here's a Leo triplet I took a while ago (on 6th, 7th, 17th and 19th April), back when there was darkness as a reasonable time. 139 x 180s subs with a 130PDS and ASI2600MC (gain 100 offset 24) on an EQ6-R with OAG guiding. All controlled by Astroberry. Stacking and processing in GraXpert, Siril and StarTools.

And after weeks of unrelenting cloud I got 3 clear nights in a row! Here's another M51. 189 180s subs spread across 2nd, 3rd and 4th April from a 130PDS and ASI2600MC (gain 100 offset 24) on an EQ6-R with OAG guiding. All controlled by Astroberry. Stacking and processing in GraXpert, Siril and StarTools. Tried drizzling to get a bit more resolution. Thanks for looking.

Where was your focus position with the 450d? Modding the camera might move the sensor slightly but unless you were pretty much at one end of the focuser's travel I wouldn't expect it to make that much difference (assuming you're using the same t-ring, etc). How does the 600d focus with a canon lens? Best thing I ever did with my 130pds is get a coma corrector which moved the focus position out. Without I think I had about 9mm of inward travel on the focuser when in focus with my 550d.

Well somewhat embarrassingly I found this hand print on the rear lens on closer inspection. Which does look a bit like a focusing mask I guess! Not managed to test after cleaning but hopefully it can be filed under "stupid things I've done to ruin a night's imagining".

Hi, Does anyone know what I'm doing wrong here? Attached is a single 90s sub (coloured and stretched in siril) from a Samyang 135mm at F2 attached to an ASI2600 at 100 gain 24 offset. All of the stars appear to have two diffraction spikes which I wasn't expecting. The spikes stay in the same orientation through 5 hours of imaging that night (and are very pronounced after stacking) so it isn't an accidental tree or washing line. I promise I did not leave my focusing mask on and there aren't any cables nearby which could have plausibly fallen across the lens. Coming from the world of 130PDS I'm expecting some sort of obvious obstruction across the lens to have caused the spikes, which I can't see so I'm a bit stumped. Thanks for any ideas!

I think you need an artificial source of light... I've got an app on a tablet which just lights it up with a white light as my telescope isn't too wide. Otherwise you can get light pads which are A3 size or bigger or there are dedicated flat field generators. Are you using bias or dark flats too? As you say for lights everything should be the same except for the exposure time. As you mention ISO are you using a DSLR? Try losing the darks and just have bias and lights. I never noticed much difference adding darks with my 550D.

I suspect it is. My 130 PDS seems to collimate in 3 different ways depending on if I use a laser, a cheshire or collimation cap. All of them seemed OK with a star test but the laser and cheshire seem to throw the illumination off centre in a picture or flat. I decided life was too short to go fiddling with focuser tilt though! Almost certainly leaking light; many people have black shower caps or similar around the base to stop light getting in when imaging. I take darks with the camera out of the telescope with its dust cap on. Unless you're using a DSLR to image in which case I wouldn't bother with darks.

Did you start from a complete new profile and let it find some suggested values? Always worth it when changing something as radical as moving to OAG from a guide scope. Are you binning? I use the same OAG setup with my 130PDS and it's definitely better with binning 2x2 the guide camera. The larger DEC error might be bad polar alignment, the PHD2 Guidelog would tell you.

Ah fair enough. Which skywatcher coma corrector do you mean? https://www.firstlightoptics.com/coma-correctors/skywatcher-coma-corrector.html or https://www.firstlightoptics.com/coma-correctors/skywatcher-f4-aplanatic-coma-corrector.html The first seems to not be good enough for F4 scopes from the reviews. Otherwise maybe post an example sub to show the effect.

The contribution for the ASI2600MM Pro to the back focus is 17.5mm.... https://astronomy-imaging-camera.com/product/asi2600mm-pro-mono

I've got the EQ6 pro too which I've been very pleased with. On decent nights I've had it down to less than 0.3 pixel RMS with an OAG through my 130PDS without any sort of tuning. Because it's such a ubiquitous mount there are plenty of tuning / strip down guides for it too if you need one. It is heavy but as long as you're relatively fit and strong it should be fine. I don't think I'd take it travelling but shifting it around with tripod attached is quite manageable for me. It really depends on how far you'll need to move it regularly and what possibilities of leaving it setup semi permanently in the garden are (getting a cover for mine made a big difference so I could leave everything setup if there were a few nights in a week I could image with) as to how much of a pain this will turn out in practice.

I've just got a Samyang to fiddle with and am using the astro essentials samyang to M48 adapter too. I couldn't reach infinity focus with 44mm backspacing from the adapter using the 2600MC either. 43mm (ie 25.5mm of spacers) allowed focus for me (and to pass through infinity). I'm not sure it's doing the best it can though as I've apparently got 10-20% tilt (depending on which program you ask). Although presumably nothing to with back spacing.

Have you tried with a focusing mask? Might be easier to be sure you're at the right "in focus" position with that and that you're really passing the in focus position when you think you are.

I haven't bothered for cold in the UK. When it was recently down to -7C it was some of the best guiding I've seen on my Eq6-R (and I've not fiddled with it at all). Like others, I'm pretty sure that was just down to seeing as I've had much worse on slightly warmer nights where you could see a bit of high cloud. I'd be far more worried about temperature and thermal coverings if I was doing solar observation in full on summer sun on a hot day.

Have a look at the field of view calculators in kstars or similar programs (or online eg https://astronomy.tools/calculators/field_of_view/) so you can check that the sort of things you want to image are going to not be too big or too small for the camera / scope combination you're going to go for. DSOs range massively in size from very large to very small.... Also it's worth looking for examples of pictures that others have taken with the equipment you have in mind so you'll know what's possible.

I think the first thing you'd need to decide is what you want to photograph and how much money you want to sink into it. Then the question is a bit more answerable! The telescopes you've listed are all fine for deep space photography but anything like that, where you need long exposures, you'd need an equatorial mount really. On the other hand you have a mak 127 so with a cheapish planetary camera (or even a mobile phone holder and a mobile phone) you could start taking pictures of the planets or the moon more or less with what you have since you can use short exposures or short videos to achieve that.

I think it probably depends on how good your guiding is but ultimately elongated stars will be the result. The bigger the ratio of guiding resolution to imaging resolution the better your guiding errors will need to be in order to have good subs. On a bad night's guiding you might not even get away with 4x.

Here's another Pleiades for the collection! About 10 hours of integration time shot between the clouds on 4th, 7th, 8th 9th and 12th of January with a 130-PDS and ASI2600 on an EQ6-R all controlled by Astroberry. Processed with Siril, GraXpert and Startools. Thanks for looking.

Wouldn't it be easier just to lose the helical focuser and use extension tubes / spacers to get the cameras parfocal? You only need to get them parfocal once (and you can do it in daylight on an aerial or something). I've never missed not being able to orient the guide camera yet for my OAG...

Here's NGC 457 (Owl Cluster) and NGC 436 together. 148 x 3 minute exposures over two nights on 20th and 23rd December taken with a 130PDS and ASI 2600. Stacked in Siril and processed with GraXpert and Startools. Thanks for looking and Happy Christmas all! 🎄

If you've got a few things to power then the Nevada Power supply is pretty good and what I use to power everything (ASI2600 or DSLR, mount, Raspberry PI, etc). https://www.firstlightoptics.com/batteries-powerpacks/nevada-psw-30-25-30a-switch-mode-power-supply.html You can use the cigarette socket to power everything via suitable splitters and adapters, then if you want to use a battery these usually have a cigarette socket too so you can just swap. Beware of cheap power supplies.

Yup but that's over three times the price of the StellaLyra and it looks like it would be imported from Germany too. I guess I was curious if people have had success with the StellaLyra f/4s or not as on the face of it they seems pretty cheap.

Hi, Does anyone have any experience with the StellaLyra f/4 reflectors? Currently I'm imaging with a 130PDS and an ASI2600 and wanted a bit more resolution on small galaxies and other DSOs. It looks like a 10" f/4 paired with that camera would give me 0.76" a pixel resolution which seems to be around the limit before it would need binning so I was thinking of that being my 2nd telescope. I haven't completely discounted other possibilities but given I'm happy with the reflector I've got I'm definitely biased towards a bigger and faster version of what I know... On the 130PDS I use a TS 1.0x GPU Superflat 4-element 2" Coma Corrector. Is that likely to be transferable directly to the StellaLyra? It moves the focus position out by 20mm which is a boon for the 130PDS as it keeps the focus tube out the way but is it likely to cause focuser problems on the StellaLyra? It would be nice to be able to transfer the whole imaging train between the two intact. I've got a EQ6-R which claims to handle 20kg imaging so it looks like it should handle the 10" at around 15kg plus other stuff. Is it too much? Too much of a wind sail? There's no observatory but the garden is reasonably sheltered. Any bits it needs out of the box, like an aperture mask? Would the EQ6 need a pier extension, extra counter weights or anything like that (it's just on the tripod it came with at the moment)? Thanks for reading, any thoughts appreciated! Stefan

Do you dither when guiding? Looks very similar to what I got from my 550D when I started guiding without dithering.

Certainly looks like the subs with my ZWO 2600 last night. Cambridge was pretty damp too. You could see the mist gathering on the front of the camera glass almost immediately after I cleared it. Did you have a look at the little window on the front of the camera? Should be obvious if it's mist or ice. I've ordered a heater for it but I'm not massively optimistic it would have solved last night's problem. Trying cooling to a higher temperature is worth a go too. My DSLR seemed to manage OK though but then it clouded over so I gave up!