Alien 13

11 hours ago, raadoo said:

The second to last (R and B swapped) is really quite pleasing! 👏

My pick too.

Alan

On 10/12/2021 at 11:36, neil phillips said:

Depends what your imaging and if you want goto ?

I do just fine on lunar and planetary and even bright deepsky unguided with only one motor (RA) and the cheapest one too.

got two motors ( both used as RA one made a ticking noise, the other silent ) For 50 quid on here. Seems to track ok with reasonable polar alignment 

I image Lunar and Planetary fine with my single axis motor that "ticks" and is fine for camera lens deep sky too. I am confused though why the std motors are often quoted as being "DC" when they are still crystal controlled stepping motors albeit with a lesser spec?

Alan

Nice and agree that phones have come a long way, I hope this brings more people into the fold as its so easy now with plenty of apps to help too.

I have just started setting up a widefield phone rig for this and general video shooting too.

Alan 

On 09/12/2021 at 09:12, TerraC said:

IOS or Android?  

Deep Sky Camera is good on Android..   Lots of settings, can program multiple exposures for stacking and supports RAW.   Seems to push your onboard camera to it's limits and offers high ISO's exp times..  Worth checking out.  

 

 

Just downloaded this and looks promising, was worried if it defaulted to the highest res camera on my S21 but it seemed to do so, I like its simplicity too.

Alan

The mount/adapters depend on if you are using the Camera on its own for widefield or through a scope eyepiece. The most important cheap addition is a remote bluetooth shutter release. I bought one of these because of its lowish latency but there are lots of cheaper ones.

My own rig is an all metal stand alone widefield one that doubles up as a video set up but not cheap.

Alan

Alan

I would drill a hole in it to make the scope 5 ft long for a start 🙂

Alan

11 hours ago, bilbs84 said:

First of all, thanks for the advice and feedback.  You've basically confirmed my own suspicions.

I remember when I shot my first test image with no tracker, stacking over 300 2.5 second exposures took forever, I understand that the processing can be time consuming, but it sucks when you only get 30 minutes or so of exposure for it.  For this reason, I thought I'd push the limits of the mount and setup to 45 seconds and see how things turned out.  I'm fairly pleased with the result, and next time, might see if it will handle a minute.  I used N.I.N.A's 3 point polar alignment to dial in the mount, I managed to get it to under 2' error.  While I'm sure that I could do better, that was about the limit that I could get with the camera taking 2 second exposures constantly while I was getting it dialed in.  Maybe next time I'll give the web cam feature of the 80D a crack and see if it can get enough exposure to plate solve with that.  At least that would cut down on the shutter count.

I was shooting the Large Magellanic Cloud on an 80D, with the EF 85mm f/1.8 lens.  Unfortunately the clouds rolled in only half an hour after I started imaging.  I ended up only being able to use 29 of the 40 frames that I shot due to clouds.  That being said, I'm pleased with the result, especially since I was able to get the polar alignment dialed in, and was able to get decent exposure times.  Hopefully we get some clear skies again soon, and I can gather some more exposures soon.

I guess the one other thing that I hadn't really thought of until I was looking through the images I shot of Orion a couple of weeks ago, is that the exposure may need to drop for really bright objects, the core was a bit over exposed.  So am I better off limiting the exposure time, or reducing ISO to keep the exposure time up, I don't quite understand entirely how read noise works, so still unsure if shorter exposures at higher ISO's vs longer exposures at lower ISO's

Anyway, thanks for taking the time to help point me in the right direction.

The 80D is one of the few/only camera that Canon made that is more or less ISO invariant so you can use it with an ISO of 200 or less if you want with no noise penalty if you brighten it up in post processing.

Alan

22 minutes ago, vlaiv said:

Here is interesting thought that I just had.

What if we change the question - just tiny bit?

Why do really expensive mounts sell and why are we drawn to them?

That question is not nearly as controversial as original one. To me, answer is rather simple and it consist of two things

1. Payload

2. Performance

There are few additional minor details - like if you want to guide or not (use of absolute encoders) - and that is it.

Not nearly as much mystique or price difference for "last few percent" as with scopes. Interesting isn't it? Maybe this is because performance of the mount is much more easily assessed?

I think you missed portability, I would argue that my Sirui camera tripod is the best on the planet...well it is for my needs.

Alan

4 minutes ago, Captain Magenta said:

Although this thread is 2.5 years old I thought I’d supplement it rather than start anew.

I keep my scopes in a utility room that’s reasonably dry but heated only by an insulated hot water tank and has single-skin walls. It used to be a garage but has been absorbed as more or less part of the main house. Things don’t seem to get rusty whereas in the shed, they do.

Anyway, I inspected my quite old (1991 I think) Intes M603 Mak today and Yikes! I noticed some obvious fungal growth on the corrector plate and on the primary mirror. I don’t recall having seen it before.

 

There was some on the secondary mirror as well. I quickly took it apart and cleaned all the surfaces with a home-brew mixture of propanol, methylated spirit (ethanol), ammonia and distilled water. All surfaces are now free of contaminants and there doesn’t appear to have been any etching. I plan to use some of the mitigations listed above to prevent its re-emergence.

Magnus

Glad you caught it in time, everyone should inspect there optics regularly and clean them if there is the slightest hint of fungus...

Alan

I am wondering if some most all some of the problems with bad corners are down to the camera, any modified DSLR will likely be miles out at F2 unless its been calibrated on an optical bench, same as a dedicated CCD/CMOS with a bunch of adapters in the image train.

Alan

On 18/11/2021 at 22:32, ONIKKINEN said:

I definitely don't have a 5cm long scratch on my primary mirror coating because a pressurized air can launched a projectile towards it while "gently" cleaning my secondary. Small scuffs probably wont matter for mirrors, but still lesson learned.

The pros sometimes use high powered CO2 from something like a Fire Extinguisher to clean their huge mirrors with no ill effects.

Alan

6 minutes ago, jjohnson3803 said:

Still looking for my "forever" scope although I'm pretty satisfied with what I have now - 80mm, 120mm achros and a 90mm Mak for lunar.  But there is that question of the "perfect" mount.  And maybe a DSLR to try some non-cellphone astrophotography or maybe a dedicated astro camera would be better.  But then I'd probably need an 80ED.  An Az-Gti could be good for longer exposures.  And I probably should rationalize my EP collection...  So yeah, I'm good...  😉

Oh wait, my 15x70s are a little heavy, so maybe a pair of 20x80 lightweights?

I am with you on the 90mm Mak, you can go bigger but loose the grab and go element and the "snap to focus" that the little Mak has.

Alan

I would agree with the above regarding 8x42 or similar, the thing to check is if the binoculars can match the "inter pupil distance" of a child.

Alan

COOWOO USB heaters for me with my camera lenses and small scopes..

Alan

3 minutes ago, Ian McCallum said:

I plan in the future to get one of the Scopetech 80mm F15 refractors from Autie @FLO, so that will be the longer OTA to go on the EQ5.  No problems regarding the bolts, as I've already been forewarned in a YouTube video. I think one set is M8 and the other is M10, so no major problems.

Never had a problem with the bolts myself provided you dont try tightening one without first loosening the other and they only need to be finger tight..

Alan

The EQ5 is a good mount for visual use provided its not overloaded if an Equatorial platform is what you want, the addition of even the single axis motor will keep most objects in the FOV for many minutes providing stress free viewing.

I mentioned visual use but it can track well enough for Lunar or Planetary imaging which is often done by short bursts of video or very wide field AP with a DSLR and say a 50mm lens but anything else starts to make things more difficult though not impossible.

Alan

No one has mentioned the Samyang 135mm f/2 yet, an ideal match for a DSLR and "star tracker".

Alan

These controllers dont work very well if you are using rechargeable batteries, the voltage from rechargeables will only be 4.8V (4 X 1.2V) which is borderline and made worse if its cold outside. The good news is that I have found that these controllers will run quite happily from a mobile phone power bank which supplies a constant 5.2 V, all you need is an old USB cable with one end chopped off and a suitable connector fitted..

Alan 

Not seen these before but look ideal for all my DSLR video accessories etc.

Alan

8 minutes ago, JamesF said:

That one is particularly irritating.  Whose hands are we supposed to use for this?  Has the recipe-writer not noticed that there's quite a lot of variation in hand size?

James

I am OK with this, for example a small child would fill his/her mitts with the right amount of rice/salad/peas/nuts/chilies etc for their needs and an adult would get a bigger portion 🙂

Alan

6 hours ago, JamesF said:

Where accuracy isn't absolutely required and because I find it awkward to use fractions of an inch smaller than quarters, I occasionally find it convenient to combine metric and imperial at the same time.  So I might measure something as "sixty-eight inches and four millimetres" for example.  I'm quite comfortable with this, possibly as a result of being taught only metric at school whilst having parents who habitually used imperial.  I don't know if my dad used metric at work (he worked in engineering at the time), but at home his lathe was imperial so that's what I was exposed to.  Even now I have my own (metric) lathe, I'm not sure what the modern equivalent of "taking another ten thou off" is.

James

I do the same although these days I cheat and often print out a drilling/cutting template and stick it to the work piece which is far more accurate for me if I am drilling some equipment face plate for example.

Alan 

8 minutes ago, bilbs84 said:

 

I'm at 38° south, so the axis is quite steep, and if the tripod legs aren't extended, it's only about 500mm off the ground.  The camera isn't the issue, it's looking through the polar scope, and it doesn't really have any provision for changing eyepieces or adding diagonals.

I did consider trying to attach a webcam to it though.

The DSLR right angled viewfinder that I mentioned solves that problem and only needs to be held against the polarscope although there are more expensive "astro versions" available like this.

Alan

17 minutes ago, bilbs84 said:

so after driving 150km each way to go and buy a Star Adventurer star tracker a few days ago, then Bricking my EOS 60D while getting everything set up while waiting for dark.  Then at least trying to polar align the mount that night and not even getting close, I found myself almost ready to give up.

I found a decently priced 70D on eBay, and boxed the tracker back up.  I was planning on using it on a Manfrotto be free tripod, but did find it to be somewhat shaky.  Lowering it quite short helped, but laying on the grass to align doesn't interest me that much.

Anyway, last night, I thought I'd at least try aligning the mount again, since the stars were visible for what will probably be the last time for a couple of weeks.  I was actually able to find the octans stars in the scope, and get a coarse alignment done.  So at least now I'm hopeful again.  But I need a better tripod.

So, that got me thinking, has anyone else built there own tripods, and what sort of designs have you done.  I was considering something out of steel.  It wouldn't exactly be portable, and it wouldn't be light, but I was thinking that might actually be a good thing?

I'd be interested to hear people's thought.

Not sure why you would need to lay on the grass as the camera has a articulated screen and one of these held against the polarscope would eliminate that.

Alan

7 minutes ago, Macavity said:

All sort of considerations might come in? The physical strength of materials? 😉

Worst case scenario is when you try to e.g. MATCH the "aesthetics" of (for me) an
Electronics (Synth) *Front Panel* and you measure across 10 knobs (9 "gaps") and
get 9.17 inches? lol. Was it made to the imperial or metric... or WHAT standard?!?

This probably has something to do with BRAND loyalty/returning customers? 🥳

P.S. Sometimes matching Tube Rings and OTA diameters can be like this too? 🤡

I have built and still build a lot of electronic equipment and as well as having to contend with both imperial/metric I often need another measure like a bottle top/fag paper etc. Even PCB layout packages get stumped sometimes if you have the "snap to grid" option turned on.

Alan

11 hours ago, Mognet said:

Thanks for that. It looks like they are quite capable performers, and certainly well suited to satellite and UAV use as they won't be prone to vibration related problems

Having the reflective surface on the "inside" so to speak also means that the coating is immune from degradation so no cleaning or colimation.  Wonder how long before mobile phones start introducing this tech for real telephoto performance in a tiny package.

Alan