raadoo

Thanks to everyone who replied, I've narrowed it down to two options (for now, at least):

1. €1400 New LS50 B600 - with later upgrades including the focuser and double-stack filter
2. €1800 Used SolarMax II 60mm BF10 - with possible replacement of the ITF if and when it rusts

Keen to get your thoughts on which is a better choice.

9 hours ago, Carbon Brush said:

I used to own a PST. As a place, point, look instrument, it was good.
Just focus then twist the etalon to see if there is anything to be seen today.
As others have reported, adding a camera to the PST was at best a faff and realistically quite a clumsy affair.

These days I get my Ha fix from a Lunt LS60. Which gives better views than my PST did.
Caveat. Performance of individual Ha scopes does vary.
The Lunt is heavier so more demanding of the mount.
I run it on a Solarquest mount, taking care with balance.
It is the pressure tuned version and I have been very happy with this method.
I can get 'near enough' by setting a pressure, then looking for the view.
Not having done a side by side with a Lunt tilt tuned, I cannot compare.
It is easy to put a camera on the LS60.
I have suffered a cloudy blue filter. 10 minutes to swap out with little skill and very affordable.

I have never used any of the Quark offerings.
I was put off buying by the quality issues being reported about 4 years back when I was considering upgrades from the PST.
Intuitively I'm not that keen on the idea of a heated etalon.
It has to be slow to respond and a thermistor/control problem is another point of failure that can't be fixed by a DIYer.
There are complete Daystar scopes for less money than the Quark eyepiece. I'm sure these have to use the bottom grade etalons.
However, there are happy users out there.

This year for white light I spent on a Lacerta Herschel wedge & solar continuum filter, on a 2nd hand 102mm achro. A lot less than Ha spend!
Great results in white light. Lots to see with the sun being very active at present. Very quick to set up.

Sorry, no easy yes/no answers. But keep looking and asking.

HTH, David.

 

Even for someone as new to solar astronomy as I, the PST always looked more like a visual tool, rather than for imaging, even with potential upgrades. From what I've seen around the forums, the most use imagers get out of a PST is to cannibalise its etalon and then Macgyver it onto a doublet. And while that's well within the realm of many an SGL'er, the consequences of getting something wrong are far too disastrous and permanent for me to attempt. i.e. I'm quite fond of my eyes and would like to keep them going for as long as I can. 

For once, the mount isn't going to be an issue with me, as my mount can easily move an 8" SCT / 5" APO; the kind of solar scopes I can afford are nowhere near that kind of payload.

I'm also quite nervous about the whole Quarks need time to heat up. Not necessarily because of wasted time - thought that's definitely going to get old real fast - but more so because electronics will generally break long before analog mechanisms do.

The Achromat + Herschel + Solar Filter route is definitely something I've considered and seems to be the most cost-sensitive option for high quality safe solar imaging and viewing. Trouble is I've got this annoying condition of being in love with Ha 😆

9 hours ago, michael.h.f.wilkinson said:

I hav eimaged with a humble Lunt LS35 THa, a Coronado SolarMax-II 60 mm,  and an APM 80mm  F/6 triplet with ERF, Baader TZ-4 4x tele-centric Barlow, and a Solar Spectrum 0.3 Å H-alpha filter. In the latter I could only image parts of the sun and needed to stitch the result. The differences between the set-ups can be seen below (click for full size view)

If you can get something like a secondhand LS50 or 60, or a SolarMax 60, that would be a great start.

Thanks so much for taking the time for such a comprehensive reply! One hears (and reads) a lot about how aperture is king but in reality, I'd be happy even with the results you got from the LS35. I have seen a used SolarMax II 60mm BF10 available but I'm slightly put off by the potential rusty ITF issue. However, I am not one to shy away from a bit of tinkering so if need be I think I could probably replace the filter if and when it rusts over. It's available from a retailer I've dealt with before so I should be able to RMA it if it's a faulty scope. Alternatively, I could do a bit of saving and get a new LS50 and, in time, replace the focuser (reportedly the worst part of this scope) and, later still, double stack it.

25 minutes ago, inFINNity Deck said:

I think that indeed it is wiser to get a dedicated scope to start with.

May I suggest (if you not already have done so) to search this forum and the SolarChat forum for examples of what you want to achieve and choose the make and model based on that? When you go for Lunt and want to do imaging then the pressure tuners are the way to go, as the tilt tuners generate ghost-images. Getting rid of Newton-rings can be done using a camera-tilter or by adding an ADC in the imaging train (I use the latter).

A highly recommended read (before buying a scope) is C. Viladrich, e.a., Solar Astronomy: Observing, imaging and studying the Sun, (Saint-Lys, 2021).

Nicolàs

 

Fantastic tips, Nicolàs!

Thanks for the detailed answers @Elp & @inFINNity Deck !

Sounds like neither the Quark, nor the entry level offerings from Lunt or Coronado/Meade are long term scopes and would likely lead me to think about “upgrading” down the line. With solar scope prices being what they are, I think it’s probably wiser to step up to a dedicated >60mm H-alpha scope from the get-go?

With your equipment, @Budgie1 is on the right track recommending a dual narrowband filter. I had the Optolong L-Pro, now have an Optolong L-Enhance and recently got the Antlia ALP-T. For as long as I've got an OSC, I'm not letting go of the Antlia. Worth every pence. With the change from a cool grand you could look at an EAF if you don't already have one?

I'll join the myriad of SGL members asking for scope suggestions, as I'm well aware that October and its imminent partial solar eclipse are not that far into the future and I should really get some practice with solar imaging before those glorious few minutes of occlusion. Let's make a short list of things to keep in mind:

• Used primarily for imaging (H-alpha)
• Reasonable priced, <€2K
• Reliable (I've read too many horror stories of rusty filters and sloppy focusers)
• Available, i.e. not having to wait for three months for one

And a couple questions I hope you may be able to answer:

• Is Quark-ing my Askar FRA400 a better route?
• Smaller aperture new scope or larger aperture used scope?

I happily invite any left-field alternatives to the above.

Just like @edarter and @Avocette, I too use APP for stacking only. Unlike @edarter, I find APP's interface quite intuitive - much more so than PI's WBPP.

For me, the advantages vs something like DSS are that it makes loading multi-night frames a trivial task. I usually image over 6 or more nights and I find it quite easy to load up flats and lights for each session, while masters have their own load function. I also appreciate the options to play around with various algorithms to compare results. And I echo @Avocette's comments on the Light Pollution Removal tool - just brilliant.

After stacking, the resulting fits file goes straight into PI where it goes through a bunch of acronyms before exporting separate TIFF files for the background and stars into PS.

I'll shamelessly butt into this thread as I've recently moved and have access to quite a bit of unobstructed sky - up until now I didn't have a view of East at all, so going for M16 was high on the list. I too fought with poor guiding and the low altitude of M16 from my location (I'm at 46 N), but I did manage to get just under 10h of 5min exposures with my ASI183MC Pro from my light dome of a Bortle 6 location.

4 hours ago, Icesheet said:

I did see that but it might be stretching the pennies a bit further than I had planned. Having said that it’s a significant birthday this year. Maybe I could treat myself 😆

I’ll have a read round to see what’s being said about the 135E. 

For what it may be worth, I'm over the Moon (pun intended) with my little RST-135 (non-E).

If the HEM27EC delivers on better performance than the regular 135 because of the encoder, then it's worth stretching those pennies.

4 hours ago, Icesheet said:

I’m not expecting great unguided performance based on the other harmonic mounts. As long as it can hold a loaded Esprit 100 with no counterweights and guide sub arc sec RMS I’m in!

There's a HEM27EC with encoder that comes in at under half the cost of an RST-135E. if it comes close to how RST-135E owners report unguided performance, it should be a considered option.

You're bang on with a lot of your assumptions. I'd say this is a case of less more is more and suggest you approach light pollution reduction from multiple angles:

• I wouldn't go over 60s subs in your Bortle 7/8 with an astro camera. That number would be 30s for me, with a non-modified DSLR.
• The L-Extreme is good for strong Ha targets, but you may find that it's a bit too strong as a general / always-on filter. I'm quite happy with the L-Enhance, having been somewhat disappointed by the L-Pro.
• Proper calibration frames are always going to yield better results than synthetic solutions in software. Flats are going to have the biggest impact, but darks, biases and, in my particular case, dark flats are also important and looking back now, I'd never shoot without them.

Affinity is a fine piece of software but it's not what I'd call dedicated and it's likely that tools like Astro Pixel Processor or PixInsight with their Light Pollution Removal and Dynamic Background Extraction tools, respectively, will help you more with removing those pesky gradients.

For astronomy cameras, where there is no shutter, there's no benefit to delaying exposures.

The reason one is advised to employ such techniques with DSLRs is to avoid what is commonly known as mirror slap. A DSLR's mirror rising to allow for an exposure creates vibrations which could ruin a long exposure if not allowed some time to settle. With astronomy cameras, the only settling needed is after a dither.

@ONIKKINEN I ran a quick test with my ASI183MC Pro, indoors, doing 100 biases after cooling it to my usual -10°C to test if the quick exposures would create enough heat to move that temperature point. Cooler was running at 60%-70%. I can report it didn't move around more than + / - 0.1°C. So I guess that's one data point that says the ASI183 cooler does a good job?

15 hours ago, bomberbaz said:

Anyway, uncooled and unguided = lots of short subs in a quick time with higher gain than long exposure guided is the way.

If I get chance I will get another go of M33 using my 60mm svbony guidescope, see if I can better it. 🤔

I hope you do get another chance at M33. Do keep in mind that, while it's a large target, it's very faint. I recently had a go of it and at 3h it's not nearly enough to do it justice. Next time around I'm putting in at least 12h from my Bortle 6/7 skies.

1 hour ago, bomberbaz said:

All below are unguided. I cannot find raw data to give details on exposure, gain  etc.

Ring nebula, first thing I did, pretty rough.

Iris nebula, one of my better efforts, again bit of amp glow on right.

On Andromeda here I got a great central galaxy but you can see a dust mote as I had no lights and the amp glow where I pushed the camera too far. It is uncooled and I will continue using uncooled. 

I am considering using a computer heatsink to make a homemade cooler but I am still in the planning stage, I will let you know if it comes to anything.

I’ve got good news and bad news and they’re the same: that’s not Andromeda, that’s the Triangulum galaxy. So if your go-to failed to get to M31, at least you can be proud of having gotten quite a usable image of M33 - which is more than I was ever able to with my own AZ-GTi (but, hey, mine’s a lemon of the yellowest kind).

2 hours ago, CraigD1986 said:

Ah that’s interesting, thanks.

Long story short, Alex at FLO recommended getting the ZWO UV/IR Cut filter to use between the ASI533MC-Pro and a sigma camera lens. I thought I might as well “upgrade” to a light pollution filter as these also do the job. L-Enhance/L-Extreme are on my wish list but I assumed I would only be able to use these with emission nebulae and nothing else. So you you think I might be better scrapping the L-Pro and getting the L-Enhance for L-Extreme instead?

I don't have any experience with ZWO's UV/IR Cut filter, but I can vouch for the Baader Neodymium IR-UV Cut as being a solid choice. The other one I have and hate with a passion, on account of it giving me halos, is the Optolong CLS-CCD which, as you might imagine, I don't recommend. The Baader is what I use on broadband targets, like this M45 I recently did.

If I were starting out today, I'd get the Baader and the L-Enhance, with provisions for either the new L-Extreme or the Antlia ALP-T for the really faint stuff in dark sites.

7 minutes ago, CraigD1986 said:

Is the L-Enhance good for all targets? I thought it was best for emissions nebula only? (Correct me if I’m wrong, I’m still new to all this). Does the L-Enhance act as a UV/IR filter too?

• Good for all targets? - No, best used in emission nebulae and strong Ha targets (i.e. not galaxies or reflection nebulae). I did try it, just for kicks, on the Moon once and it didn't do a lick of difference 😆
• Does it act as a UV/IR filter - Yes. As it's a pretty tight dual narrowband filter it blocks everything ~480nm and everything over ~680nm. Obvious PSA: don't use it for solar stuff.

5 hours ago, CraigD1986 said:

I’m quickly learning that a bucket of money is probably the best thing to have to this hobby. I did have an L-Extreme filter in my basket but read somewhere here that new versions are due to be released soon.

I'm in a Bortle 6 as well and having used the L-Pro and now the L-Enhance, I say go for L-Enhance. It's a good middle ground between the L-Pro (which didn't kill enough of my light pollution) and the L-Extreme (which is going to require longer exposures and, therefore, good guiding).

I don't have a temperature sensor (yet?) so I've set my EAF to refocus every 30min. Takes about 3 minutes for the focus routine to run and then it's back to imaging, so I don't feel like I'm losing that much time. I haven't had any problems with this approach, yet, and there have been quite a few nights when the temperature dropped significantly throughout the session.

Milk carton mod worked wonders for my AZ-GTi's RA but recently found the Dec to be really stiff. So much so that it would move North, but regardless of speed it just wouldn't budge South.

Naturally I took it apart (seems to be an AZ-GTi owner's favourite hobby) and found that the grey washer that sits in the Dec wheel was a mangled up.

So, I'm gonna try the old milk carton mod on the Dec - this time aiming to keep the thing as flush to the inset of the wheel as possible, as the original (now mangled) spacer / friction plate(?) is quite loose fitting.

Will report back on findings.

14 hours ago, Macroscopic said:

I’ve tried to read (and understand ) about the potential pitfalls with a harmonic mount on CN and to me the largest issue will be guiding. I haven’t read all 90+ pages of the RST135 thread, however it would seem this post was the most interesting.

How will everyone else who is/may be taking the plunge be guiding?

As I’m new to AP I think I’m going to get a WO 50mm guide scope, ASI 462MC (as it’s very IR sensitive), IR pass filter and connect it up to the ASIAIR Plus.

This is what I'm getting from my RST-135 with a 290MM Mini, 1.25" Red filter and 0.5" guide exposures, through the dinky little ZWO OAG. That silly little OAG isn't holding the 290MM quite right and I'm getting elongated stars but that doesn't seem to negatively affect the guiding. You shouldn't have any of those issues through the WO 50mm guide scope, though.

Shot in the dark, but can you share your data here so we can try it ourselves and see if we get the same result?

I echo what the others have said. Nothing stands out as strange, other than the far too many APs (I usually shoot for <500).

I'd also recommend going for a lower percentage of frames to stack. Looking at the quality graph, I'd try something more in the line of 15%-20%.

Can you post a screenshot of your AS! interface, please? There may be settings other than APs that are causing this.

I’m as electrically illiterate as they come so my take is that overkill is underrated. Having made sure everything in my kit runs on 12V (most of our bits and bobs do), I basically go for the most amount of amps as I can get. That way I never run out of power mid-session. It also gives me piece of mind that I’m very likely future proofing for any new [power hungry] gear.