Louis D

My collapsible observing stool that collapsed into a heap after one or two observing sessions as detailed below:

I think it stayed together for most of one observing session.

Probably because greater separation just means losing more edge rays (I think they're diverging between groups), unless a wider eye lens group is used to capture them, and so a narrower apparent field of view results.  Give it a try to see if the AFOV narrows with increasing separation.

Here's my images I took yesterday of the annular solar eclipse.

I had to travel north of the actual center line that was south of San Antonio, TX to the central part of town to escape dense clouds.  It cooled off about 10 or 15 degrees at the peak of the eclipse.  It got eerily dimmer, but not dark.  It was kind of like putting a dimmer switch on the sun.  Because I was off center, I could not get a nice round ring of fire image at maximum eclipse.

Here are some photos I took through my Canon 55-250mm lens on an EOS Rebel T3i set at 250mm with a Daystar solar filter:

And here are some close-ups through my ST-80 with Baader Solar Film with a Celestron 8-24mm Regal zoom set to 8mm taken with a Galaxy S7 phone camera afocally:

Had to travel north of the center line that was south of San Antonio, TX to the central part of town to escape dense clouds.  It cooled off about 10 or 15 degrees at the peak of the eclipse.  It got eerily dimmer, but not dark.  It was kind of like putting a dimmer switch on the sun.  Because I was off center, I could not get a nice round ring of fire image at maximum eclipse.

Here are some photos I took through my Canon 55-250mm lens on an EOS Rebel T3i with a Daystar solar filter:

And here are some close-ups through my ST-80 with Baader Solar Film with a Celestron 8-24mm Regal zoom set to 8mm taken with a Galaxy S7 phone camera afocally:

On 30/09/2023 at 09:12, jjohnson3803 said:

Maybe this? 

Orion 600

 

I've owned one of these for 20+ years.  It's great as a background for my eyepiece photo shoots.  It would probably work well as a wall chart.

1 hour ago, Ags said:

I noted the Nirvana view of Jupiter was significantly bigger than the Svbony set to 4 mm. Perhaps the Nirvana is more like a 3.5 mm focal length.

I photographically measured the Svbony to have a 4.3mm central focal length shrinking to 3.1mm at the edge.  I have no idea about the Nirvana, but Ernest measured it at 4.0mm for the Meade PWA version.

The only reason I've found to use a 1.25" diagonal over a 2" diagonal in a 2" or larger focuser is due to lack of back/in focus with the scope or usage.  This is common with Takahashi refractors in particular.  It also crops up with binoviewers.  The latter need at least 100mm of back/in focus due to their optical path length.  2" diagonals require about 40mm more back/in focus than a 1.25" diagonal for the same reason.  Combine them, and now need 140mm of additional back/in focus exacerbating the problem when using BVs.

Most non-Tak refractors tend to be designed for use with 2" diagonals for monoviewing.  A few refractors have removable section(s) for native binoviewer usage.  Check specifications before buying to see if the scope will meet your needs.

Check your eyeglass prescription.  If you have low astigmatism (CYL or Cylinder) of 0.5 diopters or less, you can probably get away without using eyeglasses at the eyepiece.

You can put your glasses on a retainer leash around your neck to keep them handy for looking at the sky naked eye.

Get a pair of single vision eyeglasses set for distance vision for use at the eyepiece if you insist on using them or absolutely need them.  That way, the entire field of view will be in focus at once.  Online stores can make you a pair for a very reasonable price.  Get the lowest index plastic lenses (generally cheapest and thickest) to minimize chromatic aberrations off axis.

The Pentax XW (70 degrees, not the newer 85 degrees ones) line of eyepieces is also an excellent choice for long eye relief.

If you use slower scopes (Maks in particular), the Baader Hyperion line can work well.

Binoviewing is best for solar system objects.  Monoviewing tends to win out for DSO viewing.  Some folks never get on well with BVing.  It tends to be a bit fiddly.

On 01/10/2023 at 10:14, RT65CB-SWL said:

Only downside is it makes the ‘scope back/tail end heavy.

That, and it moves the focal point away from the design point adding SA for SCTs.  I'm not sure about Maks, though.

Here's a British review: https://www.skyatnightmagazine.com/reviews/telescopes/altair-150edf-apochromatic-doublet-refractor-review

I used TO eclipse glasses in 2017, and everyone agreed they were much sharper than the cheap eclipse glasses most folks had.  I also used to have a glass TO solar filter.  It was good, but not as sharp as the Baader solar film.  That, and it was prone to pin holing, so I got rid of it.

BSF is not nearly as sharp as a Herschel wedge, so there's always room for improvement in full aperture solar filters.

I've wondered if a high quality ERF could be made for white light visual use without a line filter.

On 23/09/2023 at 16:15, drdre2030 said:

I didn't know what bortle was, but just looked it up and I'm in bortle 5, just on the outskirts of bortle 4 by 500m, so easy enough to potentially go where a little less light pollution too.

Generally, the skies in the direction of lower light pollution will be noticeably darker.  That would be the direction to hunt for DSOs.  It tends be opposite from where there has been a lot of development.

39 minutes ago, ollypenrice said:

but it lasts for decades and uses normal batteries which you can find anywhere

Just watch out for AA battery corrosion.  It totally mine even after replacing the battery holder.  I bought two used replacements, and neither potentiometer still works.  Both go from off to full scale just before reaching full travel.

By contrast, the little lithium CR2032 button cell in my QuikFinder is still going strong after 20+ years with no signs of corrosion.

7 hours ago, drdre2030 said:

My 10 year old daughter has had a fascination with space for a little while next and so looking at a cheap option starter telescope to see if it something she will continue to be interested in, or just a phase. I've not used a telescope since I was probably her age either, so basically know nothing!

Hopefully, @PeterStudz will chime in.  I believe he has a daughter in the same general age range and recently purchased a telescope for the two of them to explore the skies together with.

There's also a Multi-Target Red Dot Finder that might be made by GSO and sold under various brands such as Agena.  I have no idea if they're any good, though.

ScopeStuff also has a Telrad Base with Orion/Synta Dovetail Foot.

3 minutes ago, Stu said:

I fitted a finder shoe to the base of my Quickfinder so it fits to a standard base, and does not fall off.

Scopestuff do one, but I’m sure it would be easy enough to get one 3D printed.

http://www.scopestuff.com/ss_rqfe.htm

I have the RQFE from scopestuff, and it works very well:

There are quite lightweight, large Dob options out there, they just cost a lot.

I actually like watching the moon drift through ultrawide to hyperwide angle eyepieces at high power when using an undriven alt-az mount.  It's kind of like watching it rise and set in a way.  Of course, each eyepiece can cost as much as some telescopes and equatorial mounts.

Put the camera in Manual (M) mode, set the ISO to the lowest setting (ISO 200 or thereabouts), and set the shutter speed to 1/60th of a second for starters.  Increase or decrease the shutter speed as needed to get the best exposure based on rear screen previews.  You'll still want to bracket your exposures around that best value because I've found that images look quite different on a large computer screen once downloaded and reviewed.  You can always check the EXIF data in the photos to find out which ones look best on a big screen.  Once you know what shutter speed works best, note it and use it exclusively next time.  You'll need slightly slower shutter speeds to capture the Galilean moons better.

Your 127 Mak is quite a slow lens at f/12, so getting the exposure down to a reasonable level shouldn't be too difficult.

Good luck to your wallet!  You'll soon be sliding down the very expensive and slippery slope that is astrophotography. 😄

16 hours ago, rpdayton said:

My experience in such things has been in installing and setting up CNC machines; I have learned that these scopes work completely differently.  I am used to using spring washers that are able to apply constant force against a moving component, hence my assumption this connection would work similarly.

Just compare the price difference to understand why the difference in mechanical sophistication.

4 hours ago, Cosmic Geoff said:

Here, I found that an increase in contrast brings up nebulae in the iphone image nicely.

It seems odd that a device intended to make it easier to see faint objects wouldn't automatically increase contrast in transferred images for immediate viewing.  Is the idea to make you still feel like you're looking at a faint object through the eyepiece?  I would think sophisticated image processing software could bring up the contrast without ruining the image.  Perhaps that will follow as an app to download and run on the phone's sophisticated CPU and GPU.

Using a screen grab of the Wizard nebula from the next post's video, I did a quick edit.

I performed levels correction , saturation boost, and mild sharpening in PSE 2.0 followed by a mild noise reduction in Noiseware.  All tools are 20+ years old, so it shouldn't be too hard to have these filters available in real time in some app.  Before is on the left, after is on the right.  I think it makes it a whole lot easier to see the nebula.

1 hour ago, rpdayton said:

This year I'm ready to just put the whole thing on the curb and post it on facebook.

Perhaps you could try mounting the OTA on a manual alt-az mount and simply push it to objects using a RACI, RDF, QuikFinder, etc as guides.  There are various planetarium apps to help you find your way around the sky.

23 hours ago, marggaze said:

I suggest the Meade 8x50 Straight-Through Viewfinder, it's really great telescope accessory as for me. I use it for finding objects in the night sky and it has a large field of view and a focus adjustment knob for sharp images.

I have one as well as a GSO RACI.  At my age, I'm finding it incredibly difficult and painful to contort my body to use a straight through finder much above the horizon.  Otherwise, the views are very similar between the two.