BrendanC

I've been thinking a lot about filters recently, and whereas everyone says it makes sense having one filter doing Ha and O3 and another doing S2 and O3, I just don't see the logic. Surely, if you combine the data from these two filters, you're going to get twice the amount of O3 than Ha or S2? And in fact given that the bayer matrix has twice as many green pixels, this would actually result in four times O3? Am I missing something?

Outstanding. I'm particularly impressed you got the Angler Fish. Thanks, this is very encouraging.

Thanks Lee. I guess that you don't even bother with broadband then?

I've come across his site before, and in fact it was after reading it that I decided to opt for an OSC with dualband filters as a next step, after trying mono and not really enjoying it. But, even Bristol, at Bortle 7, isn't London. I'm specifically referencing London, specifically DSO.

Sure, and I know someone who does great solar system stuff from London, but I'm just doubtful that if I were to want to continue with deep sky, I'd be able to do broadband. It seems narrowband is the only game in town (or city for that matter), and as @vlaiv says, extreme conditions are probably going to warrant an extreme approach ie very narrow filters with very long exposure times.

Hi all, I started out in astrophotography about three years ago, taking advantage of the Bortle 4 skies where I currently live . I shoot deep sky objects - nebulae, galaxies and clusters. However, I may be moving back to London some time soon, and am considering my options if I want to continue with the hobby, given that it's one of the most light polluted areas in the world! I understand that solar system photography is possible, but would probably require a whole new rig (I have a Sky-Watcher 130PDS, NEQ6 and ASI533MC). I might be able to continue with deep sky work if I use narrowband filters for emission nebulae, but would broadband be possible? For reflection nebulae, galaxies, clusters etc? Any takers? Thanks Brendan

Sure, but this is for the HEQ5! They do both for the EQ6 too, but not NEQ6 that I can see. I've emailed them. Thanks for the pointer!

Thank you - they don't seem to have the logo side though, but I could ask.

Does anyone know where I could buy these: https://www.opticstar.com/Sky-Watcher-Name-Plate-Latitude-Scale-Plate-NEQ6.html ? Ideally in the UK? They say they're out of stock.

Hi, did you get anywhere with this? Looking for the same myself.

I got a great response from Michael, the maker of the spider vanes, and in fact just realised he's accounted for this on his website too. From https://www.backyard-universe.de/en/i/installation-secondary-spider

Thanks both! @vlaiv I take your point about them adding interest to the composition, but I was just very surprised at how pronounced they were. I can't see any other similar effects on Astrobin versions of this object. Still, if you like them, then that's cool. Cuiv the Lazy Geek has also fitted this vane, which came with flocking (of a kind) already applied by Backyard Universe because he's a VIP (!), which is why I thought this might help, see https://youtu.be/I5C0bjwfL_w?si=fur-KTFWGqw-GE6L&t=808 @ONIKKINEN I separated out the stars with StarXTerminator, and this is in the starless layer. I take your point that I could probably edit them out, but I'd rather not. Actually I'd rather they were in the star version because then I could just stretch the stars less and could potentially mitigate this.

Looking for advice! This is just over an hour's worth of LDN 1251, the Anglerfish Dark Nebula, and I was surprised to see such pronounced diff spikes. They reach right across the FOV (they're not sat trails, I checked). I recently had the Backyard Universe spider fitted. I know this needs many more hours' worth of exposure, so if press on, will this mean I need to stretch the background less, and the spikes should recede? Or, should I be thinking about flocking the spider vane? Any other recommendations if I continue to gather data on this object? This is with a 130PDS and ASI533MC Pro. Thanks.

I'm actually planning on using Robin Glover's Conesharp app.

Thanks Ivo, I'll give it a try.

So, I had the problem again last night. (calling @Yoddha in case he's around, let me know if the latest log would help cos I'm desperate now...) The mount kept flipping back and forth, always calculating the object as about 6,000 pixels away. At one point it stayed on the correct side, but as it solved to get near the object, each plate solve was further away, something like 250 pixels, then 500, then 625 etc. Finally, after about an hour, after much probing and checking to see what could be wrong, it stayed on the correct side and continued. I'm stumped. I ran an alignment plan before the shoot to make sure the mount was properly synced. I could clearly see that the mount was pointing west but it kept flipping. I've checked every setting I can think of, including laptop time settings, EQMOD, APT, I just don't know what's going wrong. I've increased the delay to 20 minutes for next time but I'm pretty sure that's what I had set when it failed previously (I decreased it to 15 hoping the alignment plan would have helped). Any suggestions because this is starting to feel like a hobby killer. One random thought: is there a case for cone error causing the flip problems? If the scope isn't orthogonal, could this result in enough of a shift in the view after the flip, for the mount to think it needs to flip back to get to the coordinates? I really don't know, it's just a crazy idea I'm putting out here.

I thought I would see quite a wild cone error, as you say, if this were the case. But it really doesn't look bad to my eye. The calipers idea is a good one, and in fact I just used my digital calipers to confirm that the spider is absolutely spot on, so it's not that. I'll definitely check out the screws as you say. I also intend to polar align with the NEQ6's PA scope, then verify with SharpCap, just to make sure SharpCap isn't throwing me a curve ball, as well as try ConeSharp to address any cone error. I'll get there eventually, I hope, but I really could do without these never-ending issues...

Good call on the ring screws, I never considered that. They seem OK but I'll make absolutely sure they're tight (I was sure before!). Apart from that, well, other people have mentioned cone error too, so that's the leading candidate so far. Looks like I'll have to learn another arcane mount-related technique...

Just bumping this one in case anyone else has any input? Opinion is divided as to whether this is cone error, poor polar alignment, the new Backyard Universe spider I recently had installed, or something else entirely...

Actually, very quick question while I'm typing: what would you recommend as starting values for Flip Moment and Delay Flip Move? I can see from the user docs that they're both set to 5 minutes, but Delay Flip Move should perhaps be a bit longer? This is with an NEQ6, 130PDS, ASI533MC Pro, near Oxford in England.

That's good to know! That's assuming I have cone error, but it does look like that, plus general misalignment of the rig, are at the root of a lot of my problems. I think maybe it just wasn't until I attempted the Dark Shark that these issues came to light. I still managed to get something though, after combining the good stars with the nebula. Hopefully I'll clear out these other problems in tonight's session. Thanks for your help again Ivo.

Phew, good to know! I think the first thing I need to do, tonight if possible, is to physically align my entire rig so that Polaris is as central as possible when in the parked position. Currently it doesn't even appear in the view when I polar align. This hasn't been a problem before, but clearly it's an issue now, and it's even possible my mount has shifted over time (I keep it outside permanently, under a tarp, and just put the scope on to shoot). Also, as I said, I think I have cone error, which I've never had to address before, so that will be fun and games with Conesharp too. So many moving parts, so much to go wrong...

I don't use Sync - I just use GOTO++. That's what I've always done! If I should be using Sync then that's something I've been doing wrong for about three years...!

Hi Ivo, Thanks for responding. The EQMOD limits are whatever the default is, I believe just when the RA axis is horizontal. I'm pretty sure I have the correct location coordinates, as I've been using them for three years with no problem. I think you're right about misalignment of the mount. This has been brought up elsewhere, so I need to physically move my rig around until I can see Polaris when it's parked, to get the mount closer to where it thinks it's pointing. I'm also getting double diffraction spikes when I stack before and after the meridian flip, which implies cone error. So, I need to sort out my rig! I'd already sent the log file to your astroplace support email, but I've just sent the very latest (with 2 appended to the file name), complete with screenshot of the meridian flip settings. Thanks again, Brendan

You know, this sentence did actually make me LOL, albeit in a rueful, resigned kind of way... So the Dark Shark hits around 68 degrees alt, which I guess is pretty high. I've also had problems with meridian flips during this shoot, which I'm wondering might also be down to plate solve errors exacerbated as you get nearer Polaris (still waiting for someone to help with that issue too). I mean, the workaround is to process the nebula without stars, which I would do anyway, and then just use one set of stars rather than both. But, I don't like workarounds, and I don't like knowing something's wrong with my kit. Even more, I don't like knowing there's something wrong with my kit that I don't know about. Even so, as you rightly say, there's always something wrong. My recent set of issues has covered tilt, collimation, calibration, non-functioning camera, non-functioning focuser, non-functioning mount, spider vanes, pinched optics... the list goes on. Then, you get one chance every few weeks to see whether you've fixed it, and another totally ridiculous, random problem pops up. I've been through so many barriers and jumped so many hurdles this year, I don't feel I've progressed at all. I stayed up till 2am last night to babysit the supposedly automated meridian flip (which still didn't work, you can read about it here if you like https://stargazerslounge.com/topic/412762-calling-apt-astrophotography-tool-gurus-meridian-flip-failed-need-help/ )which, given I've been doing automated flips for nearly three years with no problem, as well as stacking images before and after flips with no problem is just, as I say, random and ridiculous. Thanks for the help again, and the wry philosophical observation.