rnobleeddy

On 08/01/2021 at 14:16, teoria_del_big_bang said:

Yes you can, but like I say in my experience the Wifi does not work well at any sort of distance with the internal WiFi adapter on the RPi and I have found a 2nd usb WiFi adapter or using Ethernet works a lot more reliably.

Steve

I've done some playing around with this and for me, the Pi's wifi strength is great until I stick it behind a large metal telescope! If you have a way of maintaining a clear line of sight between the Pi and the WiFi signal in the house, it tends to do well. Once it's behind my telescope it's often unusable.

However, I did find that a decent quality separate USB WiFi receiver helped signal strength, as did adding a WiFi repeater by the back door.

The coma corrector needs a specific distance between it and the camera's sensor. This means you can't add the vari-lock spacer and in your case, appears to mean you can't focus the camera (and even if you could, the coma corrector would not do what it's meant to!).

There's a good explanation of what's needed at https://www.baader-planetarium.com/en/downloads/dl/file/id/483/product/3004/mpcc_mark_iii_instruction_manual.pdf 

Worth bearing in mind that I've seen second hand older modded cameras advertised cheaply. For example, I bought then sold a 450D for £120 and bought a 550D for £140.

You can also get second hand bodies unmodded on ebay very cheap - I picked up a slightly worse for wear 550D for £80-something.

What I'm getting at is that you may well be better off getting two separate cameras. Although I've never had time to do a side by side comparison, it really seems like you want an astromodded camera for astronomy, and a non-astromodded camera for day to day use.

On 01/01/2021 at 00:00, barkingsteve said:

You could try M27 ( Dumbbell ) Which is an easy target or NGC 2359 ( Thor's Helmet ) which is a little trickier. They give a nice colour contrast, here is my M27 from earlier in the year with the altair tri band, 130 p-ds and 294mc pro. This is a 15 second exposure  x 20 frame stack.

On 01/01/2021 at 00:23, tomato said:

By far the best bi-colour result I have obtained to date with the IDAS NBX dual band filter and a OSC camera is the Veil Nebula. As you have indicated, most other nebulae I have targeted are predominantly red. I did capture some blue signal on the Spaghetti Nebula, which surprised me given my relatively short integration times.

Thanks. The ring is now behind my house, but will give that a go when it reappears. Presumably other planetary nebula would be good too, but until I get a recently acquired 250PDS up and running, they're all a little small for my 130PDS.

As an aside, I got some data from the last few nights with a full moon using a dual band filter. The full dataset is hard to use due to strong gradients, but the red/ha channel is serviceable and led to some decent B&W images.

I used an EQ5 earlier in the year. I started with dual axis motors and then got the goto upgrade with the stepper motors. YMMV but I found:

- I couldn't get good guiding in Dec. Therefore polar alignment was key, and I'd just try to balance exposure time with % of discarded subs. Lots of people got much different results and I assume it's dependent on the particular mount, balance, tuning etc. I was probably a little over the 5kg weight limit for imaging.

- the Dec motor definitely helped as did guiding, so definitely go for the dual axis motors with the ST4 port on the controller

- The goto motors didn't lead to any particular increase in guiding accuracy for me

- there are lots of stepper motor projects out there for the EQ5 but none I found that are both commercially available and sensibly priced

31 minutes ago, alacant said:

I think things are changing though. 

Have a look at the Optolong l-extreme for example.

Cheers

If you use one of these, do you have a link to some example images? I use a similar STC filter and I'd like to know if I'm getting results that are comparable to others?

16 hours ago, wimvb said:

+1 for Telescopius. You can create your own catalogs with favourite objects.

Another +1.

The only downside is that it tends to lead to me imaging what's best positioned/brightest each time we get a clear night. On the positive side of that, it's stopped me imaging things that I have no chance of doing a good job of.

8 minutes ago, Desmond said:

I will give that a go for comparison. Good idea.
Just wondering why I spent all that on a filer in that case!
When would a filter be preferable then, given I'm in a Bortle 4 area?

Thanks for the help - much appreciated!

If time allows, a comparison would be interesting!

Generally, the dual/tri band filters are best suited for emission nebula. They tend to be marketed with photos of the veil nebula and I've found that target works exceptionally well using them. Unfortunately, it's now a little low in the sky.

On other targets, for example the North America nebula, I've found I get a much cleaner image with the filter, but that it's hard to get anything other than red color, as I imagine the Ha signal is dominating. I'm going to have another go at processing some of the data, but for now, I've only been really pleased with the veil. 

That said, I don't see a lot of OSC images that do show nebula in glorious color - my guess is that it's just so much easier to produce pretty images with a mono setup.

Quote

Also, I was wondering, with all that expensive electronic equipment left outside gathering condensation all over it is that bad/potentially going to kill the electricals? Mostly thinking about the star adventurer and canon 6d body here... I’ve never had a dslr, and only initially bought it for astrophotography but my wife loves the photos it takes for real life too, so want it to last, and can’t afford to invest in another.

Clearly there are no guarantees, but I'd be less worried about this. Mounts should have been designed to handle this, and from what I've seen, the electronics are generally far enough inside and the gearing greased well enough that it shouldn't be an issue. My Canon DSLRs have got pretty wet from dew in the past and still work fine. 

I use a similar filter + DSLR. I'd suggest

- longer exposures - if your mount can manage it, as long as possible, with 300s tending to be typical (this was explained to me well by another member recently, but it's likely that at 1 minute exposures, the read noise of the camera is the dominating factor in your noise)

- more total exposure time - I don't see good results (usually) until I've got 2 hours of data, obviously that's somewhat target dependent

- trying again when the moon isn't at 100% - even with a narrow band filter, the moon has a big impact

5 hours ago, Anthonyexmouth said:

The 15m USB cable has served me well for years, when i build the pier i laid conduit to the little workshop at the back of the garden with 12v / 240v and cat6 to the pier with the intention of running the setup from there but as it turns out I prefer my warm house and the reclining chair more than the cold workshop. 

I think Stellarmate is just a polished version of astroberry for with a £50 price tag which for simplicity in setup might be worth it.. 

whats it like operating remotely with the Pi, is there much lag? 

 

It's not as smooth as running locally but with decent wifi it works fine for me. You can run the software locally and just connect to the Pi as a server, although I never quite worked out if this improved matters, depending on if you move the subs over the network. May be worth a try if you find it slow.

Works fine here - no issues at all, other than ensuring a good WiFi signal when the Pi is directly behind the scope. 

I have the 4Gb version and it's never close to using all the RAM, so I don't think 8Gb would be useful for astroberry, but may help you if you also use the Pi for something else.

Mainly I'd suggest being careful with the hardware you use - not everything works well (or at all) with Indi, for example, a number of the ZWO USB2 planetary cams have issues.

14 minutes ago, paul mc c said:

My budget would be around £ 500-600,which for me is a lot of money as i no longer work after an accident,which got me thinking should i just upgrade my 450d to a higher spec dslr,or just keep going with what i have and put the money towards something else.........

I haven't seen any detailed comparison, but a few people have suggested that moving up to the Canon 18MP sensor produces better results. I personally found this to be true -  the 550D I use produces noticeably cleaner images than the 450D. However, this tended to only be an issue after processing if I was short of data. When I could get 30+ 5 minute subs with large dithers between each one, the noise in the final image tended not to be an serious issue in either case.

But YMMV and newer DSLRs may be much better. Certainly I never really worked out if (for example) all 18MP Canon sensors are the same for astro work, or if more expensive cameras are somehow less noisy. I'm also not sure if I'm getting typical results - posts above suggest the color 383 shouldn't be any better than a DSLR, whereas I found that the data was much cleaner.

Edit - on the other hand, my 550D cost £20 more than the 450D, so probably worth the cost!

12 hours ago, Dixie said:

A bit tangential, but second hand prices for lots of CCDs as far as their owners are concerned have not quite kept up with current events. Astro Ads seems full of hugely optimistic valuations, especially for 8300 chipped cameras. 

Yeah, I've been trying to buy stuff second hand and see this all the time. Just because a camera cost £2000 ten years ago, doesn't mean you'll get anywhere near that for it today. 

My take is that the volume sold is pretty low and so it's hard to find a consensus that way. And most astro kit hold it's value well.

There's also a pretty big gap in value between a cheap DSLR and a cooled camera. I bought a modded Canon 450D for £120 and yet there's not even a lot of choice in second hand cooled cameras until your budget is over £600.  For £600 you're not going to get anywhere close to 5x better images, and will have to put it with a smaller sensor.

I own the color one and whilst I haven't used it much, I got some shots with it that I'm very happy with. Aside from sensor size, I'd say it is well ahead of an uncooled DSLR (at least for me, I use a 550D) - when it comes to noise reduction in startools, there isn't any visible noise with the 383L, whereas it's always a key step with the DSLR. 

Whether it's useful or not somewhat depends on price - if I could choose a free 550D or a free color 383, I'd take the 383 by quite a margin.

23 hours ago, bendiddley said:

Hi. I stumbled upon this post whilst researching 12v hubs. Just wondered how you got on with the deepskydad box? Thinking I would quite like something similar to this. Cheers.

The only negatives are that it took a little while to arrive (maybe 2.5 weeks) and the finish isn't as professional as the more expensive alternatives (i think it's 3d printed).

Definitely recommend it - it's great value for money. I've used it with a few different setups and must have been drawing close to the maximum current a few time and it's been rock solid. I power everything from it, including the mount, raspberry pi, camera, dew strap and focuser.

Realise these threads may seem a little lazy but there's quite a lot of options so I'd value any opinions.

I've been using OSC cooled CCDs and a DSLR for about 6 months. Enjoying it but really like how the narrow band images look, especially the Hubble pallete, and I find myself using a dual band filter with the OSC more often than not. Live in bottle 5.  Scopes are a 130PDS and a 250PDS. Happy with the 130, yet to decide if the 250 is practical. Mount is an old EQ6 that guides ok. 

So looking at mono camera options. Budget is £1500 if I sell my current OSC cameras and filters.

Wondering what sensible options might be? Ideally, I'd like 

- as big a chip as possible - going from DSLR  to smaller chips has been painful so if I only have one camera, I'd guess 4/3" diagonal is the smallest I'd consider

- narrow band and lrgb filters

- it all to work with ekos/astroberry

- happy/eager to buy 2nd hand, not in a massive rush

A second hand asi1600 seems like it's stretch my budget but there's a qhy163m with filter wheel and all 7 filters (baader) within budget on ABS.

An older kaf 8300 should be in range, and I've seen the odd sxv with larger chips in the price range before. 

Other possibilities include just using the mono with narrow band and keeping the DSLR and a CLS filter (costing about £200 in lost sales) or just waiting to save some more money?

Just wondering if anyone has any targets that they've found to produce good results with a dual (or tri or quad) band filter with a OSC camera, such as the Optolong extreme or enhance filters?

All the listings and materials use the veil as examples and I've found that the veil easily gives the best results, as the OIII is presumably strong enough and in a separate region to lead to the distinct red/blue colors.

Whilst I'm sure the SNR is improved on every target, everything else I've imaged ends up a slightly disappointing shade of red, like the pac man nebula below. Obviously there may be more one can do in processing, but I've struggled to do a lot more with this is in startools.

I have an older EQ6 without a permanent setup (although a good cover means I leave it out quite a lot) and I'd definitely recommend the HEQ5 instead. I never owned a HEQ5 but I've used an EQ5 and it was much easier to move around. I'm a pretty large/fit guy but the EQ6 is a lot of effort because it's awkward as much as it is heavy.

The HEQ5 appears to be the sweetspot - unless you want the extra weight capacity of the EQ6 (and most don't) then it's cheaper and isn't going to have significantly worse performance if you get the belt mod.

I'd probably recommend skipping the EQ5 - whilst some people have got good results with them, my experience is they take a lot of effort/tuning to get solid guiding accuracy.

I haven't read all of this but my take is:

- most processing is CPU limited so you can just rely on the CPU benchmarks, so CPU benchmarks absolutely matter

- for most people, an upgrade won't yield massive increases in single core performance (but 20% single core performance will help!) so check if your software is multi-threaded.

- I use DSS and Startools and they're happy to use all the cores, with Startools also running well with a GPU

- Regardless of whether it helps overall processing time, getting the fastest storage you can will make for a happy life! 

45 minutes ago, vlaiv said:

I'm not sure what you are asking here, but here is breakdown of what happens:

If there is read noise in camera - only noise source that adds per exposure and is not dependent on exposure length - stack of few longer exposures will have better SNR than stack of many shorter exposures both summing up to same total exposure time.

This is because all other noise sources depend on time and stacking them is no different then exposing for longer. Only one that does not behave like that is read noise. It has the same intensity regardless if you expose for 0.1s or 100s.

Just how much difference there is between few longer subs vs many shorter subs totaling same overall exposure time depends on few factors - biggest one being ratio of read noise to other noise sources combined or rather biggest of rest of them in simpler case. Other factors include stacking algorithms used - sometimes sigma clip produces better results than regular average and it works better when there are plenty of samples to establish statistics.

There are other things that play in short sub favor - one of them being how well your mount guides. If your mount guides well for 5 minutes - that does not mean that it can go all night long as there are factors that are on larger scales than that. What if you have differential flexure that becomes obvious on exposures longer than 5 minutes?

So, guiding/tracking can and will set upper limit. Second thing is wasted subs. What if something interrupts your imaging session - a bird landing on your scope, sudden gust of wind, neighbor turning on their light, earthquake (yes that does happen), ... You can either loose 20-30 minutes of imaging or loose 4-5 minutes. This is down to how often you expect for odd thing to happen.

Choice of exposure length is ultimately a balance, and yes you should go with as much exposure length as it makes sense with all above criteria.

Thanks. I was referring to the error introduced by the mount, and that itself was in relation to the help you offered in another thread, where for my CCD, it would take 20 minute subs would keep the read noise at the level you recommend.

The point around differential flexure is one I'd forgotten. 

Either way, I managed to get 10 x 20 minute subs last night with pretty poor guiding and the subs are OK (as an aside, I believe this was a combination of moderate gusts of winds but I appear to have had auto-meridian flip turned off, and for some reason the tracking degraded after the mount passed the  meridian. Once I spotted it was about to crash and flipped it, guiding was a lot better). There's a slight elongation in the stars in one axis, but I'll have a play with dropping some of the worst subs from just before I flipped from the stack. 

So I guess that's a long way of saying I think I'll be fine when guide performance is better, so just need to balance the exposure duration with % of lost subs.

3 hours ago, vlaiv said:

Depends on your setup.

- simplest rule - as long as you can while still having tight stars.

- complex rule - determine read noise for your camera (in electrons) and see if LP noise or thermal noise is higher for your conditions (will depend on ambient temperature and light pollution levels) and then make exposure such that read noise is 1/5 of higher of the two - thermal noise or light pollution noise (very similar to above given advice - except you should not do it in ADUs but rather electrons and you have to see if thermal noise (dark noise) is higher than LP noise).

Or simply go with 4-5 minute exposures

 

As an aside, and something I was going to ask you in a different thread...

My old mount was poor and would occasionally jump by many arcseconds in DEC and would take so long to recover that the subs were unusable. Keeping subs short was essential because I could just throw away the ones that had a large jump.

My new mount isn't amazing, but is pretty consistent over time - if the guiding is RMSE of 0.8" then it's pretty much bouncing around all the time, rather than guiding well sometimes and having the odd bad spell. Is there are reason why, for example, 1 x 20 min sub would suffer more than 4 x 5 minute subs? Naively the signal would just add, so once I'm exposing long enough to average out the random movement, it won't matter how longer I expose for?

I'm not aware that's possible to damage a camera with overexposure. It's a very common thing to do.

Try a different PC/different cable. If there's no change in what you see on the screen when you move the camera from a dark to a light place then it doesn't sound good, but I'm not familiar with QHY cameras.

3 minutes ago, Stuart1971 said:

Why can’t you use darks with a DSLR, I did all the time...the only issue is you need to take on the night of imaging after or before the lights....but it works extremely well....same sub length and will be same temp too, which is the important bit... 👍🏼😀

In fact with the canon DSLR I had it could be set to automatically take a dark of the same sub length after each light frame, this obviously doubled your imaging time if you did after every image, so I just tended to do at the end in one go...20 or so...

Whereas with a dedicated Astro cam you can build a library at any time with different exposure lengths and temps...

Yeah, I get that it's possible, I just can't justify losing half of my imaging time. I'd also never been particularly sure that taking them all at the end works as you could easily have a 5 degree temp swing. 

Perhaps I'm impatient as I'm new to this, but if you add up the cost of kit and compare it to the amount of imaging time I get (between needing to work/sleep, but mainly clouds) then I'd actually argue that a cooled camera is well worth the investment to double one's imaging time! 

On the flip side, I found that once I have more than 20 or 30 subs, dithering works a treat. Again, I've got lot to learn, but this certainly feels like an area where more subs also improves matters. Most people appear to recommend dithering over darks, but clearly, if you have time, darks + dithering would be best.

1 hour ago, wimvb said:

As I wrote before, check out Stan Moore's chapter in "Lessons from the Masters"

I've ordered a copy. Whilst it may not be everyone's idea of fun, I remember a lot of CCD vs film debates from my PhD group many years ago, so I look forward to learning!