ONIKKINEN

37 minutes ago, wuthton said:

I'm sorry but this isn't true, you can take some fabulous images with some very modest equipment if you keep your focal length short and your sampling rate high. If I was re-buying today, a big mount would be a long, long way down on my list of priorities. A cooled camera and some nice filters would take the top spot for the big money.

Depends on the targets in question if focal length and resolution is a big deal or not. Wide nebulae: sure small scopes and mounts are fine. Galaxies: small scope will be disappointing.

DSLRs are plug and play and easy to learn. Astrophotography has many hoops you need to jump through and many tricks to learn to get going so starting simple is probably wise.

DSLRs vary in price quite a lot but not in astronomy-significant specs so pretty much any Canon or Nikon would work.

APS-C sized dedicated astronomy cameras start at 1400€ and get rapidly more expensive  so not sure they fit your budget.

18 minutes ago, Enceladus Dan said:

Now I’m just starting with guiding I’ll be flying and can’t wait to see how my images improve.

Guiding will make the backlash issues much worse, if not taken into account properly.

RA backlash is mostly irrelevant as the RA axis is under constant motion. Balancing east heavy makes the gears touch at all times= backlash irrelevant.

DEC backlash is a problem though. If yours is really bad you nay need to purposefully polar align not perfectly to allow DEC drift to be always to one direction and set DEC guiding pulses to only happen to that direction. You may also need to abandon DEC guiding completely if you lost the Skywatcher monday morning product lottery (i did).

Another trick you can do to deal with a dodgy mount is to shoot at higher declination targets. Close to the pole you can get away with a lot of issues in the mount because the sky moves so slowly.

12 hours ago, 900SL said:

Not harsh.. just accurate, in my experience 🤪

Agree with this. My mount is embarrasingly bad and poorly designed.

9 hours ago, Louis D said:

The back focus distance would refer to the focal plane of the eyepiece which is generally close to the shoulder or reference surface of the eyepiece where the lower insertion barrel widens out to the upper barrel.

You could simply add M48 spacer rings screwed into the bottom of the eyepiece that would then screw into the top of the CC as one approach to get the required 55mm of spacing.  This is how the Baader MPCC is generally used with eyepieces.

Alternatively, you could try to use it with an eyepiece holder such as the Baader ClickLock with M48 female thread, again with M48 spacer rings as needed to reach the proper spacing.

I have some unused spacers and a 2 inch to 1.25 inch threaded adapter so sounds easy enough. I also have a few different types of eyepieces so i assume these could have slightly different placements of the focal plane as well.

I would also assume that its not a millimeter science for visual as it is for imaging. I can tolerate coma somewhat in visual but not at all for imaging, so a somewhat uncorrected field might not be noticeable.

10 hours ago, Iem1 said:

Thank you for the suggestion!

I just restacked in 32bit, but with compression. No way I could do without it. And I was getting pretty horrendous results in DSS, not sure what I was doing wrong but it was coming out a bit of a mess in comparison to SiRiL

result.tif 206.25 MB · 2 downloads

Il have a play with this too and see if I notice any improvement  

I think there is a pretty big difference between the 16 and 32 bit versions. I don't see nearly as much "separation" of values in the 32 bit (not at all really) whereas the 16 bit version has clear lines where one brightness part of a nebula jumps up to the next one. You have really good data here and i would be very happy to have captured this! I threw this through my processing routine, which changes every time so this might not apply for every project, but it goes like this:

Siril: 1)crop, 2) background extraction, 3) Photometric CC with a manually set star magnitude to something that i believe is reasonably well captured in the data. In this case i just chose mag 14 as these stars are still pretty good in your shot. Export to 32bit .fits while still linear.

Astap: Bin 2x2 to improve signal to noise ratio. Not sure if this was necessary or beneficial. Still, i see ne obvious negatives so hey why not.

Siril round 2: Asinh transformation, full 1000 whatever units they are. Histogram transformation with the autostretch function and then dial it down a bit to preserve stars. At this point the data is stretched and the precision is no longer needed and i convert to 16 bit.

Photoshop: Create starless and just stars layers with StarXterminator. Stretch the starless layer, saturation on the starless layer (just the iris blues pretty much in this case with the select and mask tool). Camera raw adjustments to texture/clarity/dehaze on the starless layer. TopazDenoise denoising and sharpening to the starless layer. Then on to the star layer which requires usually less work: Saturation until star colours are nice but not nuked, slight stretch to brighten a bit (i did not stretch enough in siril round2, ohwell) and then finish the layer with just sharpening to the only-stars layer with TopazDenoise. Combine stars and the nebula layers and done! Im just about to turn into my second year of astrophotography so not an expert so these might not be the best tips or methods but thought i would "think aloud" on what i did.

Here's what i got:

As a mainly galaxy imager i had to scour the image to find at least one faint fuzzy and i found just one: UGC 11678 in the top left, close to the "tail" of the Iris!

I have a TS Maxfield 0.95x comacorrector in my VX8 that advertises a 55mm working distance for the backfocus to a camera sensor.

But which part of the eyepiece is the 55mm to, if it even applies to eyepieces like it does for sensors? The corrector does not advertise visual use in any way but i would assume there is some way to make it work. Just thread in an adapter or two and something to hold the eyepieces and should work?

This thread has piqued my interest. Most often i am stargazing from a B6 zone, would you folks say it makes a big difference to get a UHC filter on applicable targets? Mostly i just avoid fuzzies because its a bit disappointing from the skyglow perspective.

Having played plenty of Kerbal space program and being at least novice-level familiar with the topic i can say that this will definitely work.

Thing is, 17 000 mph is nothing and the projectile they are using (i think it was an anti-tank round if i remember correctly?) is very light. Physics will win and the asteroid will accelerate probably fractions of a mm/s^2. If this is measurable it will be a success.

Its all about F=m*a. In this case the force and mass of the projectile are tiny while the asteroid is large=acceleration will be very small.

In Kerbal space program i have slammed several hundred ton-mass spacecraft at orbital speeds to comets and they simply do not care. The orbit is virtually unchanged because of the insane masses involved. So a realistic significant redirection is not going to happen any time soon but this will be an interesting real world test and proof of concept.

The newer creative cloud version is only 12€ per month. You get all the usual apps like photoshop, lightroom, canera raw, bridge etc. I dont really see how saving 12€ a month is worth the effort of piracy and using outdated software.

You dont have to have the creative cloud app open or be online for photoshop to work and you also dont have to update your apps when new ones roll in.

I noticed that the raw stack you posted above is in 16 bit mode while still linear. Its very likely you have lost a not insignificant amount of signal to this! Stacking in 32bit mode takes a lot more processing time and power but you should still always do this.

I have noticed that stacking my 26 megapixel frames takes around 1 gigabyte per sub with SIRIL. Easier and less straining on your PC to do in DSS, but SIRIL stacks a bit better IMO. If you have no extra harddrive space to free up, try stacking in DSS to get the 32bit result as i think it would be better?

I notice price fluctuations with mounts a lot. In TS the EQ5 was under 800 eur for a while and now it is back to 879eur. Supply shortages: the movie, part 2 electric boogaloo all over again? Or just price updates for other reasons? Who knows, everything is too expensive anyway 🤣.

2 minutes ago, CaptainKingsmill said:

Can I just weigh in that the EQ3 and the EQM35 are not equivalent, and the EQM35 is definitely not significantly worse than an EQ5. 

The EQM35 is a perfectly capable mount for entry level astrophotography, and actually has a higher rated payload (although only by a little) and greater precision than the EQ5 due to it's 180tooth RA gear and modern design. It also has a higher degree of flexibility as it can be used in RA only mode which might even be more useful for OP.

That being said, OP just has a camera and some lens's, even a EQM35 would be overkill. Something like a star adventurer as @jefrs has suggested would be perfectly fine for his current needs ( and probably a sturdier tripod)

 

All of what you said of the EQM35 is marketing fluff and hearsay. The 10kg payload is based on the fact that if you slide the counterweights all the way to the end the mount is technically capable of slewing a 10kg payload and nothing more. It is NOT suitable for astrophotography with such payloads. The true imaging payload should not exceed 5kg and ideally the imaging payload would be 0kg.

The greater precision part is partially true. It does have more teeth in the RA axis to potentially reduce the effects of periodic error, but this does not matter since it had NO BEARINGS to hold any weight. The moment you introduce guiding you notice that the sticky besringless RA of the EQM35 will not do the job. In this case the 3 and 35 are very similar where as the 5 is clearly superior. Dont even get me started on the DEC axis with 1-4 seconds of backlash, tight spots, loose spots, stiction, flexure.

The modern design consists of: an EQ3 DEC axis (junk) and a slightly improved RA axis that still does not tackle the main issue of no bearings. The mount will have unfixable mechanical weaknesses unique to the EQ3 class of mounts. 

Didnt mean to attack you specifically but the mount in this case, so im sorry if it came out like that. It just really grinds my gears seeing people use the same justifications to save 50€ as i had when buying mine. The fact is you dont get 50€ less mount, you get perhaps 300€ less mount (comparing 35 and 5).

I don't think 500 eur is going to be enough for any astrophotography mount, unless you find what you're looking for in the used market.

500 eur is just barely enough for a Skywatcher star adventurer or Ioptron sky guider pro. Neither of these come with a tripod, so you would have to use the current one (which is not great, since its falling over?). These are also not really meant to be telescope mounts, but just trackers for a camera and a modest sized lens. These have a motor in them to track the night sky as the Earth is rotating. With these you will still need to manually find the targets you're shooting. If you have a DSLR and a decent lens, getting either the Star adventurer or the Sky guider pro and a better tripod is probably the closest you can get to your budget.

The under 500eur EQ5 you were looking for is the version without the motors and motor controlllers, so just a fully manual equatorial mount. This will not be helpful for astrophotography as the tracking is what you are looking for. This is the version with the motors GO-TO capability at 879eur: https://www.teleskop-express.de/shop/product_info.php/info/p3800_Skywatcher-EQ-5-PRO-SynScan---equatorial-GoTo-Mount-with-Tripod.html . The EQ5 is actually a decent mount and will definitely hold your DSLR and lens (with a few bits in between as adapters) or a telescope at somewhere around 5kg comfortably. It will also hold a slightly heavier telescope but things will probably get more difficult with each added kg more, so probably not a good idea to go much over 7kg. The EQ5 with the synscan GO-TO system will aim itself towards the targets you're looking for (after an alignment procedure) and then track this through the night. Equatorial mounts also require you to polar align them first, so that the tracking will be aligned with the Earths rotation.

Buying a mount smaller or "worse" than the EQ5 is not a good idea, the cheaper ones (EQ3 and EQM35) are significantly worse than the EQ5 for not much money saved. You might think you can get away with using the cheaper mount and just "work it out" but take it from someone who made the same mistake: It will not in fact work out and you will end up hating the thing. Saving just a bit more money gets you a much better product!

5 minutes ago, kentnek said:

Hmm I didn't think of that. Perhaps next time I should put the iPad on my lens hood to allow a bit of distance between the iPad's screen and the lens elements, and use a white shirt or cloth to diffuse the light further. Thanks for the input!

If the lens hood was on for the lights, it should be for the flats aswell it could have an effect too.

You can actually just retake flats now/anytime later and stack again. Try to have the lens on good infinity focus and the aperture/iso as it was for the lights. Wont be perfect in terms of dust on the lens but otherwise should work. Many folks reuse flats taken months ago so it will probably be fine.

I used to take flats from a computer monitor on the day after shooting and as far as i know they were at least decent.

31 minutes ago, kentnek said:

@ONIKKINEN I placed an iPad on my lens 🤣 All other settings are the same except for shutter speed, which was set for 50% peak in the histogram.

Looks very bright, although it is difficult to judge from a picture. Too bright flats can be bad and not capture properly because the exposure time is so short. I suppose there could also be internal reflections between the lens elements and the ipad surface that are different from your lights?

Try putting something in between and/or reducing brightness. A white t-shirt folded in layers and tightly rubberbanded on the lens would work. 

Also light leaks from the area you are shooting from to the lens surface could be an issue, but i doubt it would leave such a perfect circle. The top left bright spot looks more like that and is not that big of a deal.

Unrelated to the banding issue but your flats dont seem to be working all that well, given the weird circle effect.

The circle is present in your uncalibrated lights but not the flats, so it does not calibrate out. How did you take the flats?

It should work, however long USB cables are a bit of a gamble sometimes. I had a project (astro unrelated) long ago and found that some active cables work while others don't. The usual solution that works really well is the more expensive wireless control options where you have short cables scopeside and control the thing from elsewhere wirelessly.

But you dont actually need the zwo asiair to do that, you can use any other type of mini-pc to do the same thing and some options are a lot cheaper. Raspberry pi running stellarmate or a cheap windows 10 mini-pc running anything you want are also options. The ZWO asiair really only has ease of use in favour against the alternatives, since you are limited to only ever using ZWO products with them. ZWO products also can carry a price premium so you would end up saving a lot of money going the other routes.

2 hours ago, newbie alert said:

I'd add a third of the filter thickness, but the standard 55mm isn't a concrete figure.. machining tollerance comes into play... once you start to use Plate solving software you will find that  manufacturers native focal lengths are rarely right

Also think this is the case.

Mine should be 855mm but it is consistently plate solved as 840mm. Also my backfocus should be at 55,5mm but i added 1mm more to reach a better result. So the correct amount of backfocus is probably not set in stone.

Did you download and install the FTDI chipset drivers for the cable?

3 hours ago, Iem1 said:

Does this look washed out? Debating if I should be doing either 30 or 60 seconds under these conditions.

Yes it looks washed out, but that is to be expected. The target does not need to be visible in a single sub, in fact i usually see nothing in a single frame without stretching and even with stretching its mostly just a jumbled mess of pixels. This is probably especially true for a dark nebula (such as the iris) because you're trying to capture nothingness, so seeing nothing is actually what you're after. What separates the dark cloud from the background is more exposure to brighten the part of the iris that is not darker than background sky. Either 30 or 60 second subs would probably work, but the 60s one looks just fine. 30s would probably work aswell, so up to you to figure out whether you want to deal with more short subs or less long subs that have an increased chance of being trailed = thrown out.

Your left side of the histogram is completely detached from the left end, so you are at least not underexposed. The right side has some possibly overexposed pixels, but looks like its just the starcores of the very brightest stars as the "line" of values in the histogram is broken up towards the right side.

B3-4 and full moon might still be better than severe lightpollution without a moon for some folks, so it will probably work out as long as the Moon is well clear of the target. Ideally the full Moon targets would be something like open clusters or globulars, which are just stars so no trouble in any conditions so in this case the Iris nebula is a difficult target.

As an example for the "single sub doesn't matter" point, here are 3 pics. The linear sub, stretched and (attempted) colour balanced and the final product.

Just judging from the single frame, either untouched or stretched you could never say what it might look like. But take a hundred? Now you have a much better guess at what sort of total exposure time you're looking for to get a good result. (3rd pic is 668x30s).

I too use Topaz DeNoise frequently. I find that it really depends on the quality of the data how well it works, but generally there is always an improvement. If the data is really bad, it wont do any magic tricks and the final result will look like a painting if overdone, but with decent data i find that it works really well.

I had a misty residue that persisted even after drying after one night. Like yours it was not really visible unless i tried to look for it with a light, but it was there. I think in my case it was because my newtonian was right next to my car, which was running and had an auxiliary heater running (diesel powered, lots of particulates in exhaust). By right next to the car i mean i had my mount powered from my center console 12V DC cigarette lighter with a cable through a gap in a slightly open passenger side door. Also, the auxiliary heater is on the passenger side and can shoot exhaust pretty much directly in the OTA given the right wind direction. Im pretty sure some water vapour or exhaust residue got into the mirror surface from the open back of my tube and left something on the mirror surface. Cleaned it properly and haven't seen it since, so cant be sure but i think that was the cause. For what its worth i used it for months after noticing it and did nothing about it, so i don't think it affects performance.

Now how some residue from some gas or liquid gets itself into the closed back tube of your CC i don't know. Perhaps the previous owner had it stored vertically and something dripped on to the mirror? If you look at the mist ring it sort of looks like its directly under the secondary when the tube is vertical.

Of all my eyepieces i find myself using an Omegon cronus 7mm and 9mm and an Omegon flatfield 19mm the most. The 19mm without a barlow for "general" poking around wider fields, and a barlow + any of the 3 for planets and the Moon, where i spend most of my visual time.

Also helps that these 3 eyepieces are all of the 3 eyepieces i have 😅. Every time i put an eyepiece in i think about buying more or a zoom one to cover most ranges, but i haven't actually done it for some reason yet. Maybe these 3 are enough?

Just installed the Baader diamond steeltrack on my VX8. I ended up having to enlarge the borehole itself since it was a bit too tight. It does fit in the stock hole but it chafes and who knows what happens when thermal expansion is taken into account? Just shaved a bit of the aluminum off and filed it smooth, not that big of a deal. Also of course drilled the holes for the attachment plate. Starlight deprived first impressions are very good, the focuser is solidly built and i doubt i could break it without considerable violence and misuse. No sign of tilt or flex of any kind whatsoever with a payload on it and the action itself is very smooth and not "springy" at all in the fine adjustment knob, unlike the one this focuser replaces. The weight of this focuser is also very similar to the stock one, so ill just see if i can get away with not reinforcing the tube with the clamp. I don't have an accurate scale but the old one was 0.8 or 0.9 kg and the BDS is 0.9, so i will assume pretty close.

On 09/11/2021 at 13:22, Captain Magenta said:

One extra thing. I myself have just fitted my Diamond Steeltrack to my VX8. Because the tube itself is a bit narrower than for example than that of the SW 8”, the pair of supplied shims is not _quite_ enough for the middle of the base plate to avoid touching the tube. I used some extra washers to lift it that extra 1mm or so.

Interestingly, i did not need extra shims. 1 shim per side was almost enough, but with 2 shims its easily enough.

Also i found out that i don't need to shim one side to fix tilt, since the focuser drawtube itself is adjustable in relation to the focuser body! The adjusting screws have plenty of room to play with and i was easily able to square it on axis using the drawtube up/down adjustment screws. Very welcome surprise to find this while browsing the user manual.

46 minutes ago, StuartT said:

Hmm.. I haven't bought any dedicated astro cables for my rig. I didn't know I needed to. I just get USB cables from Amazon generally.

Well, you dont (if you are using a newer EQ6 with a USB port). But you could if wanted.

Its just that Skywatcher uses the previously mentioned perhaps worse prolific branded chips inside the mount itself and in order to use an FTDI chipset you need the cable. Also you would need the cable if your mount had no on board USB.