Louis D

On 04/07/2023 at 08:57, LDW1 said:

What noise ?  Looks pretty d**n good for those that this camera was designed for ! Its not even in the highly costly AP category as has been mentioned many, many times !  I don't understand how anyone could / would compare the two ?  For some reason it is all being lost in translation don't we think !

Once I looked at the image on my cheap 27" 4K TN screen for work, I understood what you meant.  Its low dynamic range and low color gamut completely masks the dark chroma noise.  However, I first looked at it on my NEC 2690WUXI2 H-IPS screen I use for photo editing.  Its wide color gamut, high dynamic range (1000:1) showed it plain as day.  I guess it makes a big difference what sort of monitor you're using when viewing images even online.

22 minutes ago, LDW1 said:

Based on your last paragraph are you implying that prices for this gear will go down further based on the history that you seem to mention ?  We are still talking the SeeStar 50 and / or similar ?  Right now a low $500 or less !

If the market takes off beyond astro enthusiasts, such as with home schoolers, then they probably will.  If they don't find a broader market, then they will die off or become expensive niche items.  Only time will tell.

16 hours ago, Marky1973 said:

What noise reduction software are you talking about?

NoiseWare Community Edition

It was never state of the art, but this version was cheap (free).  I used the Landscape preset since it blurred fine details the least.  This got rid of most of the chroma noise everywhere, but the sky background was now milky instead of multicolored.

After that, I used Photoshop Elements 2.0 (packaged with a scanner way back when and still available for under $20 on ebay with activation serial number) to first select the entire image (ctrl-A).  Next, I repeatedly  used the magic selection tool with tolerance factors of 10 to 50 to select the brighter areas for exclusion.  I used the non-contiguous option to get everything brighter excluded.  Lastly, I used levels to push down the now selected dark background to pure black.  It might not look perfectly realistic, but it got rid of the the distracting chroma/milky flocculence in the background.

I'll be watching to see where this astro-cam market goes.  The first digital microscopes for kids were fairly expensive years ago, but are pretty cheap today.

On 04/07/2023 at 06:59, Marky1973 said:

Think this looks exciting. I've been 'out of the game' for a few years and this looks like a good cheap way to get back into things. I don't have much time for astronomy at the moment so this looks like a good option to get the bug back while I prepare the wallet for a drubbing!

I know it's not going to be comparable to 20 minute guided subs, but there are some examples over on Facebook of what you can get with a few minutes of 10 second exposures and I think it looks promising for amateurs like me

https://www.facebook.com/groups/seestar/permalink/231179049694385/

There is data included on that link and I had a play with the M51 data...20 minutes of 10s exposures in Siril....and the results are promising....not blow your socks off, but definitely promising....I have low expectations but have a pre-order in ... (I should also point out I am not the best at processing! 😁)

I hope you don't mind, but I ran the image through 20+ year old noise reduction software I was talking about to smooth out the chroma noise a bit.  I then did some selective levels adjustments in a 20+ year old version of PS Elements to suppress the false background cirrus.  I think the problem is that this astro-cam is using a tiny imaging chip prone to noise just like the P&S digital cameras from 20 years ago.

Just make sure to avoid allowing liquid to wick around the edge of the lens and go under it.  You want your cloth/buds to be damp, not soggy.

I'd try unscrewing the insertion barrel while the eyepiece is upside-down to make it easier to get to the field lens.  Just don't flip the eyepiece over since that barrel might be holding the lenses in place inside the upper barrel.

Does anyone put shock absorbing material between their mount and their pier to quell vibration ringing when you touch your scope to focus it, or does everyone focus pier mounted scopes hands-off with motors?

For vibration suppression pads, I bought 90s era pure Sorbothane insoles off of ebay and cut sections to slip under each tripod foot.  They cut vibration times with my rig from 3 seconds to 1/2 second, so I consider that a major improvement, but YMMV.

On 04/07/2023 at 08:57, LDW1 said:

What noise ?  Looks pretty d**n good for those that this camera was designed for ! Its not even in the highly costly AP category as has been mentioned many, many times !  I don't understand how anyone could / would compare the two ?  For some reason it is all being lost in translation don't we think !

This astro-cam's noise level reminds me of the noise levels in circa-2005 digital cameras.  Post processing with noise reduction software was commonplace.

Today's digital cameras are doing something under the covers to minimize such noise to an almost imperceivably low level without noticeably compromising detail.  I assume it's some sort of digital signal processing within the post-capture electronics/software.

What's with all the flocculence in the background sky?  Is it sensitive enough to pick up some sort of Integrated Flux Nebula that I've never seen in other M51 images?

4 hours ago, F15Rules said:

the big 31mm Axiom, and even this one works great with the prism..if there is any vignetting, I can't see it

You'd need to take a photo of an evenly illuminated field in the daytime with that combo and then use photo editing software to sample pixel brightness across the field to accurately determine the amount of vignetting.  I've done this with the Meade 5000 SWA 40mm in my 127 Mak which has only 27mm of clear aperture at the rear port:

On 24/06/2023 at 18:14, bosun21 said:

A while back I was going to buy a GSO 32mm eyepiece from this seller. He/she gave me a PayPal address for payment which I paid. I checked to see if my payment went through okay and was met with " Awaiting for seller to open an account "! I immediately retracted the payment. No more communication was forthcoming from him/her.

Most scammers prefer Zelle, Venmo, or Cash App because there are no fraud protections.  Luckily for you, your seller seems like a stupid scammer that hasn't really thought this through and chose PayPal.

2 hours ago, Elp said:

the heat is more of an issue so best viewing under a towel or something.

Perhaps one of those damp towels used for cooling might work, just over the head instead of around the neck:

Personally, I've been trying to work out a sunshade around the scope itself so air can still freely move across my body to try to stay cooler.  Perhaps one of those pop-up half-tent beach cabanas with roll-up windows for the scope's tube to poke out of might work:

I have had an eyepatch for decades, but rarely use it.  I think my problem was fitting it under my eyeglasses since I need to wear them at the eyepiece due to strong eye astigmatism.

On 23/06/2023 at 16:32, Elp said:

Another solution I thought of is wearing red safety glasses and a normal light,

That's the idea behind Orion's AstroGoggles.  You start wearing them early, during twilight setup, to cut dark adaptation time.  They've been selling them for decades.  I have no idea if they actually help or not.  They would just make my face sweat during our hot and humid summers.

5 hours ago, davekelley said:

Hello people

I am excited about the ZWO Seester S50  anticipated to hit the shops sometime soon.  I already have it on pre order at £459 which looks like such a great price, however, Ontario Telescope and Accessories online store (Canada),  is offering this at about £319 and claiming they can ship to my address in the UK for about £6!

They do say that when something looks too good to be true then it probably is!  Does anybody have experience of this dealer, particularly buying stuff from overseas with them please?

Where is the catch?

 

Thanks

 

Davw

Remember, in North America, you need to add sales tax or VAT to the advertised price.  Only excise taxes on tobacco and alcohol products along with fuel taxes are hidden in the advertised price here.  With thousands of taxing jurisdictions, it's just not feasible to include the taxes in online prices.  Sales taxes are collected at the local levels of government, not at the national level as in Europe.  It helps to ease property and local income taxes somewhat.

Since the 31mm Nagler has less usable eye relief than the original ES-82 30mm and its brand brethren, I'm in no hurry to plunk down $500+ for one.  That, and being the same basic design (ES copied it in large part), it still suffers from CAEP.

I much prefer my 29mm ES-92 (a surplused 12mm ES-92 missing it's Smyth group of lenses) to the 30mm ES-82.  It has much better usable eye relief, no noticeable CAEP or SAEP, a truly immersive field of view (93 degrees), and a 48.4mm measured optical field stop (52mm physically) yielding a 96 degree eAFOV.  Sure, it has progressively worse chromatic aberration outside the inner 30 degrees or so, but it's not noticeable if you look only on axis.  Sweeping rich star fields with it is an amazing experience.  It's what the old Kasai Super WideView 90° should have been, and more.  If ES could work out how to tame the chromatic aberrations without losing usable field, it would be the complete package.

A laser collimator (with or without the 45 degree window port) is also useful for getting the primary on a truss Dob back in the general vicinity of where it should be if it has shifted on its support pads and sling during transport.  You just crouch at the back of the scope and adjust bolts until the return spot coincides with the outbound spot on the face of the secondary mirror.

I believe the Luminos line was designed by the same folks who did the Meade MWA line.  Both suffer from loads of SAEP that limit the easily usable FOV.

Resale value isn't particularly good for either line should you buy new and decide to move it along later, so make sure to buy used to avoid being the one who takes the hit to the wallet.

8 minutes ago, Mr Spock said:

Having a sign in your back garden isn't a crime. Seems to me people are jumping to conclusions without sufficient evidence.

It is in the US if you stole it from a highway post.  College kids love to do this with signs with evocative messages and put them in their dorm, fraternity, or apartment as decorations.  Heck, I remember some college kids driving down a street after high winds blew down some stoplights.  They picked up one of them, tossed in the back of their pickup, took it back to their home, refurbished it with electronic controls, and now it cycles through its red/yellow/green lights in a corner of their basement bar.

Actually, I would vote for neither and recommend the APM UFF 30mm.  It has a measured 73 degree AFOV, a 69 degree eAFOV, and a 36.4mm diameter field stop.  It is sharp from edge to edge and flat of field with plenty of eye relief for eyeglass wearers.  It has basically no SAEP or CAEP.

My mushroom top ES-82 30mm isn't as sharp in the central part of the field and has loads of CAEP in the outer 10% of the field, rendering that area unsuitable for allowing planets to drift edge to edge.  Planets get split into distinct red and blue images in that region.  Thus, that extra 10 degrees of AFOV/eAFOV and 42.4mm diameter field stop don't really buy you that much extra usable field of view.  It's only pleasing to use by keeping your gaze on axis and allowing the CAEP to disappear in your peripheral vision.  For that use case, the space walk experience is definitely better than that of the UFF.  It really depends on what you want to use it for.  The original version I own is just barely useable with eyeglasses.  The current version is not.

If you don't wear eyeglasses, the 100 degree APM XWA 20mm might be a better choice for an even more immersive experience.  It is sold under multiple brands including Astro-Tech XWA and Stellarview Optimus.  You'll also get a darker background for better contrast.

I just look at the shadow of the scope on the ground and minimize the size of its shadow in both the up-down and left-right directions.  Once minimized, the sun is generally visible in a low power eyepiece.

However, I did finally bling out my white light solar observing setup as seen below:

It is much more accurate than the the shadow method.

I don't know exactly what's going on with those formulas.  I double checked, and it looks like I typed them correctly.

Try doing some online research on film astrophotography and reciprocity failure.  Perhaps there are better formulas out there.

The Canon AE-1 Program could only meter down to EV1 which is 1 second at f/1.4.

My Olympus OM-4T could meter timed exposures down to about 4 minutes or about -EV7 because it used real-time integrated readings taken off the film during exposure using a photocell aimed at the film.  I have no idea if it took reciprocity into account, though.  I never found it all that accurate for astrophotography, though; so I just used Bulb with a stopwatch to time exposures.  I'd put a black felt hat over the end to start and end exposures coordinated with the camera shutter release to avoid camera shake at the start or end.

I checked an old astrophotography film exposure reference, and the exposure formulas were as follows:

Standard Exposure Formula:

t (seconds) = f**2 / (A *

where f is the f-ratio, A is the ISO film speed, and B is the relative brightness of the object.  B would generally come from astrophotography tables.

The exposure time then needs corrected for the film's reciprocity failure as follows:

t (corrected) = [(t + 1) ** (1/p)] - 1

where p is the Schwarzschild exponent.  0.7 is a typical value for non-hypersensitized fillm.