wimvb

1 hour ago, WolfieGlos said:

how do you polar align your HEQ5?

The hand control of SW mounts has an "all star" polar alignment routine that is better than the polar scope alone (which may not sit straight in its housing). If you use a computer connection (not ST4), you can use PHD for polar alignment. Try to get the misalignment within a few arc minutes.

1 hour ago, WolfieGlos said:

it appears as though there are a few options according to astronomy tools with regards to Seeing

Don't sweat the small stuff. Nebulae seldom have fine detail, so they can look really good at >2 "/p. Galaxies need better sampling, but there's really no point in going finer than 1 "/p or so. As Olly wrote earlier, in practice you won't see much of an improvement in detail if you go beyond the lower limit. But, start by choosing a scope and a camera that you like and will operate with ease. This is more important than fine tuning pixel scale. I have a SkyWatcher Maksutov Newton for all my imaging. It sits permanently on a heavy SkyWatcher mount in an observatory, where it gives great results. A guy I know who lives in northern Sweden, used the same model scope on an EQ6-R in the field (ie he drove to a very dark site and needed to shovel snow before he could set up his gear). He sold the scope after one season, probably because it's too cumbersome to haul around as part of a mobile setup in deep snow.

1 hour ago, WolfieGlos said:

Would an OAG help with this

Yes. If you have a reflector, the mirror is probably not fixed in place (it shouldn't be or you will get pinched optics in cold weather). OAG will compensate for mirror movement, a guide scope won't. With an OAG, use a sensitive guide camera (eg the ASI290 mini) or a guide camera with larger sensor (ASI174). But make sure the OAG stalk and prism can cover the sensor of the guide camera.

At f/4 you will also need to look into the mechanical quality of the scope, especially the focuser. High grade optics are useless if the focuser can't carry the camera.

11 hours ago, Cole said:

How did i do? where do i look to improve?

That's a very nice start. Your first priority should probably be to make sure that your computer doesn't update when you don't want it to. If you have windows 10 home edition, switch to the pro edition or windows 11.

The update allows you to capture more data, which would be your next priority.

The Whale and the Hockey stick, ngc 4631 and ngc 4656. In the background a lot of faint fuzzies

Data captured 15th - 18th of april. LHaRGB with a total exposure time of 1026 minutes (17 hours and 6 minutes)

Telescope: SW 190MN

Camera: ZWO ASI294MM

Processed in PixInsight

20 hours ago, WolfieGlos said:

Hi Wim, essentially it's a decision I've been around on quite a lot in a separate thread; https://stargazerslounge.com/topic/408459-stellamira-110ed-or-sw-150pds/ , based on wanting to pull in some galaxies, price, focal length and what the mount can realistically handle. Next payday I was going to purchase it, but you're right about the slow scope and it is something that is concerning me, but resolution is not something I had considered until I saw this topic.

My skies are bortle 4, based on a website and the clearskies app.

Would the 8" f/4 newt be suitable with a HEQ5 though? The OTA is 8.4kg alone.

I started out with the 150 PDS and "upgraded" to a 190MN Maksutov Newton. Focal length wise I went from 750 mm to 1 000 mm, not much of an increase. If you take a look at my Astrobin page, you can see what these scopes achieve in a Northern European climate (link is in my signature). I also went from 1.6 "/pixel with the 150PDS / ASI174 to 0.96 "/pixel with the 190MN / ASI294. Not that I wanted a better pixel scale, it just happened to turn out that way. Any difference in the  images is mainly due to me getting better at guiding, focusing, and processing. As Olly said, there's absolutely no point in getting to smaller pixel scales unless you put that scope on a cold mountain top in a desert.

The decision between a refractor or a reflector is mainly about three things. 1. Do you mind tinkering with collimation and mirror cleaning now and then? 2. Where do you put the scope? A reflector is always more of a sail in the wind than a refractor, and a smaller mount (heq5) may struggle with that. 3. What is your budget? A newtonian is cheaper than a refractor.

31 minutes ago, AndrewRrrrrr said:

interested to know what people's opinions are on what is an ideal modern camera that would be suited to the edge8HD? 

What if you rephrase that question as: what is the best scope for your camera? Scopes come in all shapes and sizes, but pixel size is much more restricted. Most ZWO models seem to have either 3.76 um or 2.4 um pixels. The size is most likely determined by the manufacturing process and the desired sensor characteristics.

When I bought my first astrocamera, the ASI174MM-Cool, it was mainly because of its pixel size (5.86 um) and associated large full well depth. When I replaced it for a camera whit a larger sensor, I opted again for a sensor with large pixels (the ASI294MM has 4.63 um pixels). The ASI174MM gave me a pixel scale of 1.2 "/pixel, the ASI294MM gives me 0.96"/pixel.

If you want to match a camera to a non-reduced edge 8, you'd need 10 um pixels (or 5 um binned 2×2) to get 1"/pixel. The ASI342MM has 9 um pixels. Close enough. Unfortunately, there doesn't seem to be a cooled version of this camera.

46 minutes ago, WolfieGlos said:

Would the 8" f/4 newt be suitable with a HEQ5 though? The OTA is 8.4kg alone.

That would be my main concern. The heq5 is supposed to be able to carry 11 kg, but an 8" Newtonian is large, and can act as a sail in the wind. Otoh at f/4 or f/5 you can use much shorter exposures than at f/9. And a long fl telescope, even a lighter one, can be sensitive to wind gusts.

10 minutes ago, WolfieGlos said:

as I’m on the verge of purchasing a 6” Stellalyra RC, to be paired with my canons (77D and 800D), also on a HEQ5.

Why an RC, if I may ask? It's a slow scope which will give oversampled images. Oversampling means that light that should fall onto one pixel, is spread over several. Less light per pixel, means longer exposure time to clear the read noise floor. Unless your sky conditions can support the pixel scale, there's not much point in having such a long fl, in my opinion. In comparison, the Stellalyra 8" f/4 newtonian has much more light gathering power, and a more favourable pixel scale, at about the same price.

53 minutes ago, ollypenrice said:

I do my own prints on an Epson 15000 ink tank printer. It's cheap to run, does up to extended A3 and, although it's only a 4 ink system, I'm very happy with the quality.

Olly

I have the Epson ET-2850 ink tank, which is up to A4. It generally produces great images, but astro images come out with a colour cast in the background, even if the "colour picker" puts R, G and B at almost the same intensities. It may just be a set up issue.

5 hours ago, StargazerUK said:

Amazing picture

4 hours ago, Coco said:

@wimvb Thats fantastic, would look great in a frame on the wall.

Thank you, both.

I’ve tried printing my astro images before, but I was never happy with colour balance and crispnessbof the prints. Mind you, that was on my own printer.

This is a 2 pane mosaic of this popular galaxy pair

The lower half (M81) was captured during april, and the upper half (M82) dec 2021 (Ha) and march this year

Since I have the habit of aligning the long sensor side with RA, framing this duo was easy, even with the old Ha data.

I have published the two panes as individual images previously

48 minutes ago, ollypenrice said:

in reality, with the Edge HD, you are quite likely to be imaging at a completely unrealistic image scale and will need to bin your data or resize it, which isn't a problem, really.

If we are going to think this through properly, we must start with 'What camera?' and 'what image scale does this give you?'

This reminds me of a story that is told about a swedish cook who lived a few centuries ago, and is supposed to have started her recipes with "you take whatever you have" (man tager hvad man haver). In the op's case that is probable the Edge 8" and an osc camera based on the Sony 533 sensor. Binning 2x2 is easiest done by deBayering in super pixel mode. Ie, 2×2 RGGB colour pixels are combined into one RGB pixel. The 3.76 um pixels would give a pixel scale equivalent to a 7.5 um pixel sensor.

42 minutes ago, gonzostar said:

However am i presuming sum of those nights you may have moon at different phases hence different exposures, would require different dark frames? 

Keep life simple and don't worry about the moon. As long as it's not near full or doesn't show (as now), it won't have any effect. When the moon is more prominent, it will increase the overall brightness, but not deteriorate much untill it's almost full and near your target. With cmos, you want to keep the exposures as short as possible, in order not to overexpose the stars. Just make sure that you can't see banding in your images, because that means that you are exposing near the read noise floor. The old rule of thumb for DSLRs that you should have the histogram at about 1/4 or 1/3 from the left edge, doesn't apply to cmos.

I have my exposure times set such that I only can see the very bright stars in the linear image. The target is never visible (unless it's a star cluster) in the non-stretched sub frames.

37 minutes ago, gonzostar said:

Does this mean i need a set of dark and flats (with same settings etc) for each evening

if you have the cooled version, you can reuse darks at the temperature which you use for lights. If the temperature is stable between nights, you can also reuse darks. But if you shoot without cooling, and the temperature differs more than a few degrees, darks may not work. Otoh, it never hurts to try. Also if your camera doesn't have amp glow, you may do without darks. Bias frames are never used with cmos. And darks can't be scaled to be used at different exposure times. What stacking software do you use? DSS and PixInsight both have what is called "cosmetic correction", which is a way to get rid of hot pixels, without having to use darks. So if your camera doesn't have amp glow, you can use that in stead of darks.

Very nice. One question: why do you use bias frames for calibration? With cmos cameras, bias frames can differ from the bias signal contained in darks and lights. The general rule is to shoot darks and flats at the same settings as lights (temperature, gain/offset, and for darks: exposure time), in order to get consistent calibration masters.

They also mention that the new ASIAIR has eMMC storage. Does anyone know if the latest ASIAIR is still based on Raspberry Pi? The Pi does not have native eMMC support. Also Pi's have been hard to get, with world wide shortage, which is only now starting to get better. According to the specs, the ASIAIR is based on the same processor as the RPi 4B, but it seems to have a different form factor

1 hour ago, gorann said:

Well, to ZWO's defence on this detail: you would only have to focus the guide-sensor once (after you focused the main sensor), after that it will be in focus as long as you have the main sensor in focus. But a focusing nob there should not be needed if they had bothered to make the sensors parafocal to start with. Maybe it could be needed for scopes with a large field curvature, but you would not like to have that for astrophoto anyhow.

Or fast RASA systems, where focus is critical. It may be cheaper to have a focus knob and relaxed production tolerances, than no focus knob but strict tolerances. As the lady sang: "it's all about the money..."

2 hours ago, CraigD1986 said:

The focuser is original and had a little bit of play in it so it would be a good idea to replace this,

It is probably the built in extension tube that shows play. You can fix this by tightening the thumb screw as much as possible, without resorting to tools.

You can replace the stock focuser with either a MoonLite or a FeatherTouch. Both have adapters that fit. If you decide for a FeatherTouch, I hope you have a lot of patience. I ordered one last august, and so far it hasn't materialised.

Probably the last target for this season, M81 in HaRGB

Telescope: SkyWatcher 190MN

Camera: ZWO ASI294MM-Pro with Optolong RGB filters and Baader 7nm Ha filter

Integration: 3 x 2 hrs for RGB and 10 hrs for Ha, captured between april 4 and april 11

59 minutes ago, Tomatobro said:

Not a sensor for guiding but for automated exposure/gain/ black level settings

I thought that chip manufacturers used a few pixel lines on the main sensor for that.

2 hours ago, Shimrod said:

May be they will have a new range of clip in style filters that cover the main sensor but not the guide sensor - after all it's a way to make more money!

And as it's fun to speculate, I'm going to guess the launch model is a combined ASI2600 and ASI220 - so IMX571 and SC2210 sensors.

48 minutes ago, UKAstroBill said:

Struggling with the interaction with filters. If it’s mono then LRGB will be fine so maybe ok for galaxies but then problematic if you want the Ha. For OSC similar issue with dual narrowband which are now very good. can they have come up with some orientable drop in filters that only cover the larger sensor? 

Any partial or clip in filters have edges that will create havoc in one way or other. In the end, OAG may just be simpler.

Btw, from their FaceBook page it looks like ZWO will also release a new line of APO telescopes and a smaller (?) version of their mount

Cone error causes field rotation, noticeable after a flip. Cone error should be corrected by an X/Y-movement after an ideal flip. Instead, you move the mount in RA and DEC to recentre the target. It's a nuisance when imaging near the celestial pole, but the further away from it you get, the smaller the problem is.

19 hours ago, david_taurus83 said:

So 2" filters at a minimum. if you swung a 3nm filter in front of it with a 2 or 3 second guide exposure? Love the idea but perhaps ideal only for OSC?

There's the catch. You would be guiding through any filter, which limits the number of usable stars, especially when imaging away from our own galaxy. Even with an osc, using lp filters or dual band filters can be a problem.

2 hours ago, gorann said:

Thanks Wim! If we are looking at the same structures I think you can even see them in your own image: https://www.astrobin.com/0rzx71/

The data from that image was from the FLO contest. At the time, I thought that the arcs were part of the Ha data.

The data is from february 2020, but the processing is from just now.

I used the XT toolset to completely reprocess 15 hours of LRGB data on this pair of galaxies.

Gear used: SkyWatcher 190MN with ZWO ASI174MM-Cool camera. The camera was discontinued by ZWO a year or two ago. I still don't understand why, because it is a very nice deep sky camera. The sensor isn't large, but the pixels are, and the sensor had one of the highest Full Well numbers when it was introduced. The read noise is quite high, for today's standards, but if you use the camera in "CCD mode", ie with low gain, it performs very well.

4 hours ago, gorann said:

except for some smaller galaxies

some 500 actually, according to the PI annotation script. 😄

Very nice image, Göran