Adam J

9 hours ago, RJC said:

Firstly, hello everyone and Happy New Year to all!
This is my first post and I am new to the world of telescopes so please bear with me. (Please forgive the long post too)...
I have been fascinated by the night sky for most of my life so I'm not sure why it's taken me so long to look to invest in some equipment.
The three scopes I have narrowed it down to are all by Sky-Watcher. Evostar 90 EQ2, Evostar 102 EQ3, and Startravel 102 EQ1.
My main interest initially is going to be observing the moon/planets, but I know I will also want to move onto other aspects of astronomy too, including pretty much everything!

Some questions which would be great to have some help with:

1) Would it make sense to go for the ST102 as this is good for wide field stuff, but can also get decent views of moon/planets with a 6mm eyepiece with a Barlow for example?

2) Is a newbie like me going to notice a massive difference between the Evostar 90 and Evostar 102 in terms of aperture? (Just how much brighter will the 102 be?)

3) The Evostar 102 seems to be a better package all round, I.e. it comes with a 2" star diagonal as oppose to a 1.25" that comes with the 90. It also has the EQ3 mount and a few other upgrades.

4) How much difference is there between the EQ1, EQ2 and EQ3 mounts?

Thanks so much in advance!

Rob

How about this and buy am separate mount for it?

Adam 

18 minutes ago, Ian McCallum said:

Would it work with VNC and a RPi?

No idea to be honest. 

On 30/12/2023 at 20:00, notaclue said:

My brother wants to do so imaging. That is fine so he can have fun. He decided to purchase a Lenovo Cromebook laptop. 

 

Discovered a problem as you may have guessed. Firstly it is Win11. No big deal. It is new and has what is needed for USB ports and other bits all laptops have. So we get Deep Sky Tracker. This is where the problem starts.

 

Apparently Cromebook does not like the .exe file format. It is as though I am speaking French to an alien and I am English. Incompatible.

 

So how do I get my brother to start his fun if the laptop is not liking the file. Are there any other programs out there that can do what is needed to get some enjoyment. Looked in play store and seen Stellarium but that is of no use for star stacking or imaging and some others but they seen a bit dodgy.

Any ideas?

Sorry to say this but your not going to be doing any imaging using a chrome book. You need a good old windows PC with windows 10 or 11 on it. Not sure what I can suggest, there is a small chance you can install windows on it but to be honest your just as likely to brick it trying. 

1 hour ago, WolfieGlos said:

Cheers Adam.

I did think of shooting at f2.8 for the background, and say f4 for stars to combine them but it would require a lot of faff having to connect a DSLR to stop down the lens - which obviously uses a different connection compared to the 585mc I intend to pair it with. Refocusing would also be a pain - so I’ve ruled this out. Another option would be to pair it with a DSLR in the first place I guess.

I like the idea of the FMA 180, I’ve just been looking at it and the FMA135 and they are well priced - much more affordable than a Redcat which I’ve always struggled to justify for the price for a similar FOV and aperture. I’ve just had a quote from Wex for the 200/2.8 and I can get £275 for it in a trade in (or cash) - pretty good considering I paid around about £350 for it. I’ll check a few other places but as a ballpark figure that will basically pay for either of those in the Askar range. Although I’m saving for an astrocam later this year (533mm or 2600mc), I can probably justify this and it seems to be the best option to get a working wide field view.

I would go with the 180 once you have a larger sensor you would regret not having a little more focal length. 

5 hours ago, WolfieGlos said:

Thanks for the quick reply Adam.

I must admit I don’t see the same collimation issue in the second image that you’re seeing (even zooming right in on the bright star), but I’ll take your word on it.

I’ve had the lens for a few years, not long before I started Astro actually, and initially I had read it was a pretty good lens for it, maybe that was just due to low cost and the fast aperture.

I might try stopping it down again and seeing if its any better at f4.5 or f5, but at that point it’s speed is basically lost.

Would you say it’s worth pursuing using the lens at all? Initially I wanted to use it for the fast aperture but if it’s only usable at slower f stops then I’d probably look to sell it and put the funds towards a redcat 51 or SY135. 

There is nothing wrong with using this lens for astro many do, just don't expect perfection from it...or to different degrees anything else. It just depends on how fussy you are really and what software tools you have to mitigate where it falls short. Some people rave about blur X terminator and how it helps with stars, I tend to think it's cheating a bit and can look artificial to be honest, but many don't see it that way. But you can't get something from nothing. 

Its not a bad lens it's just some are better like the Samyang you mentioned. But personally I would move away from lenses due to the connection type and not being optimized for shooting at infinity.

For wide shots I use the FMA180 as I value image quality over speed. I find F4.5 sufficiently fast for my own use but I am not taking an image in a single night but over multiple nights so I don't need it to be. The new pro seems better than the original. The FMA 230 also seems to do well. 

Collimation of the optics really doesn't have to out by much at all at the speeds you are shooting at and it's difficult to see when using a OSC camera. I tend to star test with a mono camera and a green filter when looking for collimation. 

If you are removing stars.in processing then why not shoot with a fast f-ratio for the target data and then add stars in shot at a slower f-ratio in processing? Best of both worlds. 

Adam 

1 hour ago, WolfieGlos said:

Well I finally had a test session under some clear skies two nights ago. What with Christmas I haven’t had any opportunities to try during the day.

After setting up my main scope, I then set up my Star Adventurer along with the ASIAIR (which I bought in November…first time to test it as well!) and hooked it up to the 585mc and 200mm f2.8 lens. Sadly by the time I got it all sorted I could see the clouds on the horizon and it didn’t leave me long to try a thorough test before the clouds rolled in.

Knowing that f2.8 produced the poor star shapes previously, I decided to go for broke and stopped down the lens with my DSLR to f4, removed the DSLR, attached the lens to the 585mc (with a 2” Astronomik L2 filter - no UV protection on the front this time), and grabbed some test shots.

Thanks - here are some shots at f4, one out of focus (both sides of being infocus), one with a bahtinov mask infocus…and again without the mask. All 5s subs on gain 252:

What I do notice from the rings when out of focus is that they all look concentric.

With the mask on, the lines all go through the middle but I do notice there’s another 4th line near the top? Local to the star only. I don’t know what this is.

Finally, the last image without the mask, to my eyes, looks to be in focus - but each star appears to have a bit of a red ring around it? Could this be related to the extra line from the mask? I do seem to recall reading somewhere (I can’t find it now) that the lens focuses the red channel differently to blue/green and it might be best to have it slightly out of focus.

The focuser on this lens is extremely sensitive; a movement of a millimetre makes a huge difference so if I can get this working I think I’d be investing in an EAF for this.

So for me the first shot is not too bad but the second is showing a collimation issue as the rings infact don't appear concentric to me. The center of the pattern appears offset to the 10oclock position. It would only be worse at 2.8. That will be your odd star shapes.  So essentially the center of the optical axis is not passing through the centre of the sensor although that in itself can be an oversimplification in these lenses with multiple elements / groupings. You might improve it a little by trying to adjust sensor tilt something that the small sensor is going to allow you to get away with a little more than a larger one but in the end you will be fighting one problem by introducing another. 

The lens is not perfectly corrected either and the red is clearly focusing to a different point than both green and blue. 

But to be honest the cannon 200mm prime was never the best astro lens, more an ok for the money solution that you should not expect perfection from. 

Adam

1 hour ago, Coral said:

Hi,

I would like to putchase a telescope for my husband for his birthday to go with a trip to Kielder observatory.  I know nothing about telescopes and getting very confused on what to purchase.

He has never had a telescope but loves star watching, using the naked eye and an app.  We are lucky enough to live next to a very large nature reserve that has no outdoor lighting.

I like the look of the telescopes that connect to an app to help you find different items in space and would like to spend up to £500. 

Any advice on what to get or avoid would really be appreciated.

I can recommend a setup like this: 

https://www.firstlightoptics.com/sky-watcher-az-gti-wifi/sky-watcher-skymax-127-az-gti.html

Portable compact with GOTO mount that connects to a phone. 

https://www.firstlightoptics.com/sky-watcher-az-go2-telescopes/sky-watcher-skymax-127-az-go2-wifi-maksutov-cassegrain-telescope.html

Same thing above on a cheaper mount. Ignore the bad review the chap did not know what he was doing. 

Adam 

18 hours ago, AKB said:

…and number ALL of your equipment assets??!

Impressive.  You have a spreadsheet or database, I take it?

Just the mobile imaging rig. So I don't get to the top of a mountain and find I am missing a USB cable. 

On 15/12/2023 at 23:31, WolfieGlos said:

Well it is the festive time of year, but nobody likes odd star shapes!

Last night I had a brief window in the clouds for a first trial run pairing my 585MC with a Canon 200mm f2.8 prime lens, primarily since it will gather data much faster than my main scope so I plan on using this for widefield imaging of nebulae.

I've had the lens for a few years, used it for astro when I first started out and it was fairly easily to achieve focus with a DSLR, although the focus adjuster is VERY sensitive to move. I've had the 585mc for a few months, but this was first light with the lens. It worked fine with both my 72ED and 102ED. So, separately, both the lens and camera have worked - but this is the first time they have been used together.

So after getting it all manually in focus last night, I was surprised to see my images producing star shapes like christmas trees (and no, I didn't leave the bahtinov mask on!)

This was not in a corner, this was across the whole field. It did seem to improve slightly if I binned 2x2 and more with 3x3 but it was still there. Example fits files attached.

I've been trying to understand the reasoning for this, it cannot be bad tracking or wind since these were 5s subs and it was riding on top of my SF102 whilst that was taking 120s subs....and the stars in those subs are round.

The pixel size of the 585mc is 2.9µm , so with the lens I would definitely be undersampling - but is this what stars look like when undersampled?

My only other thought is that I had a 2" Astronomik L2 UV/IR cut filter in the imaging train.....and after the session I found I still had a Hoya UV filter mistakenly screwed onto the front of the lens - could this actually be the culprit?

My current forecast has no clear skies for a while, so any input appreciated so I can try next time 🙂

2023-12-15_01-52-56__8.30_5.00s_0000 1x1.fits 15.82 MB · 4 downloads 2023-12-15_01-49-44__8.70_5.00s_0000 3x3.fits 1.76 MB · 6 downloads 2023-12-15_01-50-17__8.60_5.00s_0000 2x2.fits 3.96 MB · 4 downloads

Do a Star test, post a image of a bright out of focus star in the centre of the FOV, show between three and five rings. Will let me diagnose the issue. 

On 12/12/2023 at 11:31, LaurenceT said:

I've been breaking my head for months about how to use my FMA180 on a mount using a guidescope/camera and my Asiair. The only method that "looks" remotely feasible is the one in my photos. The problem is of course the added weight to the camera. The total weight with both the guidescope/camera and the Asiair is 915g (32oz). If I decided not to guide and just use short exposures with the Asiair by itself the total weight is 622g (22oz). The Asi122mm mini camera is not in the photos as it's currently on my 50ED.

I haven't yet used this in anger so I can't say anything about tilt but I'm concerned about the strain on the whole imaging train.

Be grateful for any comments.

I side by side mount mine with the guide scope.

So one of these:

https://www.firstlightoptics.com/dovetails-saddles-clamps/astro-essentials-mini-vixen-style-dovetail-clamp.html

and two of these 18cm dovtails:

https://www.firstlightoptics.com/dovetails-saddles-clamps/astro-essentials-dovetail-bars.html

The you can just mount side by side and balance in both directions. 

easy.

There is a second one here too that i am using to clamp it to the back of the esprit 100, ignore that one, its effectively your mounts vixen clamp equivalent. 

Adam

On 20/12/2023 at 18:28, vlaiv said:

I think that 99.9% of "cosmic" rays that we capture during recording of darks are in fact terrestrial in origin.

I once recorded set of darks near wood burning stove that was not clean (it was winter time and it has been fired up day before).

I had massive amount of streaks. It appears that ash has heightened levels of radioactivity. Nothing to cause concern otherwise - but shows up in darks readily.

Well so long as the wood was not sourced from the Red forest then your fine. 

On 15/12/2023 at 12:57, Space Oddities said:

Looks like a nice mount!  

But for the life of me, why do they keep selling these saddles that will drill holes in all your dovetails? It's 2023, you can't do that anymore!

That is not a major worry for me, I don't need my dove tails to look pretty. If its digging into it then its secure. 

Adam 

Just wondering what market segment this is targeted at, the area is already crowded for Skywatcher the EQM-35 pro seems only £100 less and virtually identical capacity and in fact the EQM-35 has more teeth on he RA axis while using stepper motors. 

Has me scratching my head wondering what SW had in mind. Perhaps I am missing something obvious. 

Adam

5 hours ago, ollypenrice said:

In Photoshop I had more or less settled on the extraction of a stars-only layer for putting back onto the fully starless, highly stretched image. However, I had  an image which wasn't playing nicely this way so I tried the following.

Standard linear stack, partial stretch till stars are about where I'd want them at the end.

Copy Layer. Run StarXt on the top layer.

Further stretch and sharpen and generally process the starless till all the faint stuff is pulled out and details are sharpened, etc.

Change the blend mode to lighten. When you do this, only the stars are visible from the bottom layer and, using levels, curves, contrast, etc. on that bottom layer you can manage the stars as you wish.

I've now done this on my last three images and have found it to give a very clean, natural result. In a sense the stars in the final image have never been removed from it, they have always been present in the bottom layer.

Olly

This is not how I do it. I tend to find that blend mode lighten is very often problematic in trying to recombine stars. Normally use a star only layer and combine using screen, seems to work every time. 

Adam 

43 minutes ago, Bluemoonjim said:

I may be opening myself to ridicule here  but I think I have just witnessed something amazing. I have been trying to image the Squid Nebula this evening and just saw an image of streak of light and then becoming a bright star. Which is still there.  Has anyone else seen this or am I completely deluded and seeing some sort of optical illusion? 

6 minutes ago, Bluemoonjim said:

I'm sure this would have been picked up by someone if it is actually out there. I think this must be some kind of optical glitch either in my image train or in the capture software. Very strange. This needs some investigation. Maybe a firefly in my 'scope
 

even a screen shot would help. 

New scope from ASKAR...sort of. 

50EDPH-Jiaxing Sharpstar Optical Instrument Co., Ltd. (sharpstar-optics.com)

I say sort of because:

This is the new 50EDPH spot diagram:

V

and this is the FMA230 spot diagram:

they are identical so I am going to go ahead and say that the 50EDPH is the optics from the FMA230 in a different package.

As the FMA230 is £669 the pricing of this scope will be revealing. 

Adam 

1 hour ago, WolfieGlos said:

Sorry, I should have been a bit clearer about what I meant!

The large stars in the top left and right looked bloated to me, and that was my concern. I commented on the blue halo's suggesting that whilst I've noticed them, I wasn't concerned because it is a doublet - perhaps I wasn't clear about that. I was thinking more along the lines of whether the UV/IR cut was not doing it's job on the larger, bloated looking stars.

I don't intend to pair the camera with the 72ED for imaging, it was just convenient at the time for a test session to see how the camera worked because a) I didn't want to dismantle my 102ED imaging train and b) I didn't have an adapter to use it with a camera lens.

So I would actually say the top right is suffering from a tiny amount of tilt. 

2 minutes ago, Adam J said:

Yes that is star bloat as a result f chromatic aberration, not unexpected on your 72ED. There are better options than the ZWO UV/IR filter you are using, the astronomic L3 being one good option as it will cut more blue out. 

Adam 

On 06/11/2023 at 13:15, WolfieGlos said:

Thanks Onikkinen.

Perhaps I should have bought an Astronomik L3 UV/IR filter if pairing with the 72ED then.

I need to buy a 2" filter to use it with my Canon 200mm f2.8 lens which I intend to try it with (gives a really nice FOV - https://astronomy.tools/calculators/field_of_view/?fov[]=334||9791||1|1|45&messier=31 ), so perhaps I'll try an L2 to start and see how it goes. This would then also work if I try and pair it with my 102ED, which I doubt would require an L3.

No the L2 is the same spec as the ZWO one and will change nothing. 

On 06/11/2023 at 00:10, WolfieGlos said:

I recently purchased a ZWO 585mc for planetary imaging - and to try for some DSO as well after good reviews.

Due to ongoing cloud cover and being part way through a mosaic with the DSLR, I haven't taken apart my imaging train to try it on my main scope. So feeling a test session with the recent Full Moon, I hooked up the 585mc to my Evostar 72ED with 1x FF with a nose piece, and tried imaging some clusters. I wasn't bothered about tilt, it was more just a test to see how it performed. I intended to then capture the Moon, but clouds stopped that.....

Anyway, the blue rings to the stars are quite obvious, but the star sizes seem excessively large. This was 75 x 30s subs at gain 252 on NGC 659, using a ZWO 1.25" IR/UV Cut Filter.

No star reduction, just stacked+processed in Siril. Original stacked file also included.

 

result_2252s.fit 94.93 MB · 4 downloads

Yes that is star bloat as a result f chromatic aberration, not unexpected on your 72ED. There are better options than the ZWO UV/IR filter you are using, the astronomic L3 being one good option as it will cut more blue out. The 1.25 inch version will work fine just use the filter adaptor that came with the camera. 

Adam 

16 hours ago, pmlogg said:

Steve,

Can you tell me what the specifications are of the exposed thread at the front element?  I was wondering whether it might be possible to fit a Coronado 40mm etalon to produce a light weight, compact dual purpose OTA.

Thanks

Peter

you are probably best off emailing FLO directly via their web page. 

On 06/11/2023 at 09:24, davidc135 said:

As a result of storage in damp conditions the flint lens which was matched with fluorite had become etched and cloudy. A decision was made to regrind, polish and figure the affected second surface. The front surface hadn't been noticeably affected whilst the rear fluorite lens was pristine.

The finished objective was Ronchi tested using auto-collimation and a 12'' professionally made flat.

Hover over the images for inside/outside focus info. EDIT The hovering doesn't work but inside or outside of focus in order they are: out, out, out, in, in, out, in and in.

As the test is double pass, actual errors are doubled. The edge is turned down somewhat but otherwise the correction is pretty good I think. Spherochromatism is modest with slight under-correction in red and over-correction in blue as you'd expect.

I'll be able to test it out on the heavens when some M8 mounting screws arrive in a few days.

David

very nice, have been wanting to get into this for a while who did you get the flat from?

One thing I have wondered about this is if anyone know what the little bright nebula is halfway down the right hand edge of the frame? 

A wide feild shot of the North America and Pelican Nebula complex in SHO with HOO stars.

All subs taken between Aug 23 and Oct 23.

Total intergration: 16 hours with about 5hour 20mins per channel using my ASI1600mm pro, Astrodon 5nm filters and FMA180 refractor.

I was quite happy with the amount of detail that I got at this focal length of only 180mm with the SA GTI holding the rig nice and steady.

I think I may add more SII in future if I get the chance as alot of the highlight detail is very dependent on it and I feel it was the limiting factor in processing.

https://www.astrobin.com/z9ah6a/E/

Hope that I did not take it too far in the processing and that you like it.

Thanks for looking,

Adam
 

Not sure I have read any bad press. I got V1 when it was £350 and have considered it one of my best buys at that price, but then I have realistic expectations. I also shot this subject recently with my FMA180 and ASI1600mm pro, it frames it perfectly.

Adam

11 hours ago, scotty38 said:

Hi all, There probably aren't many scopes I've not been umming and ahhing about, the Esprit 120 being one of them, but now the Askar appears. I searched but didn't find anything and whilst I appreciate that probably nobody has one, any thoughts etc etc as it's mighty tempting given its price?

Askar 120mm APO Triplet Refractor | First Light Optics

Honestly the 115/800 is a known good objective and so why take a gamble on a new design?