Louis D

2 hours ago, StuartT said:

that sounds fine to me Louis.

Totally take the point about sweating tho! I wear a hat and use a cloth around my head for viewing

I may bring out my box fan that I use at night to blow away biting bugs.  I set it up to blow perpendicular to the scope's axis and across my body, so I don't disturb the column of air I'm observing through.

On such a short, light tube, I would recommend mounting the finder directly opposite (or slightly forward or back of, depending the RACI's CoG) the altitude bearing so as not to upset balance at any angle.

2 hours ago, TerryMcK said:

The Altair Solar Wedge has been fully tested with the sun remaining in the centre of the field of view for 5 hours of continual exposure with a 6" (152mm) aperture refractor in mid-summer in the UK. At no point did the outer prism housing become too hot to touch, a problem common with other wedges.

I wonder about late-spring in Texas.  I just picked up a Hercules 1.25" for my 90mm APO, and there doesn't appear to be any heating of the rear ceramic even around noon.  Of course, 90mm is a lot less than 152mm.

I was breaking into a full on sweat, though, making it miserable to observe.  And it's not even summer yet!

1 hour ago, Nyctimene said:

Following an idea in a German astroforum, I built a "T" -frame from 10 mm scratch plywood for my Skywatcher Heritage 130 P Flextube. Two boards of 39x15 cm, screwed together, and attached to the Dob base with some small Velcro pads, so it can be easily removed. The "T" structure is squeezed in between the dob's base rubber feet and some thick felt pieces. Works fine (but, unmodified, restricted to even/paved ground), is extremely cheap, sturdy, without giving up the advantages of the Dob mount. Have a look:

Stephan

If you'd have used a hinge instead of an angle bracket, it could have folded up flat for storage.  The rubber feet would keep it from closing during use.

1 hour ago, Kon said:

Thank you very much, that's very useful! It makes a very good point from your earlier comment about its performance.  How do the ES 52 degree EP compare as suggested by @Alien 13?

It seems a bit overpriced for what it is.  If you want to go down the ~50 degree route for premium money, there's also the 25mm Vixen SLV.

However, since you have a 2" focuser, I would recommend the 22mm Omegon Redline SW, Technosky Superwide HD, TS-Optics Expanse WA, etc.  I have the discontinued Astro Tech AF70 version and prefer it to the 24mm APM UFF for about the same true field of view when I have a 2" focuser available.  The stiff eye cup screws completely off and can be replaced with the Morpheus one if you want a more pliable eye cup.  I only retired it after acquiring a 22mm Nagler T4.

3 hours ago, Kon said:

Thanks. Which one would be considered a decent EP if in the higher price bracket? It does not have to be 60 degrees since my current 25mm is probably less.

Well, if you like longer eye relief, the 24mm APM UFF and its equivalents (Orion USA, Celestron, Meade, Altair Astro all have their own) is very good.

If you're willing to move up to 2" eyepieces, the 30mm APM UFF is just about pure perfection.

There are just too many variables to be able to make a recommendation without a hard upper limit on price.

Here's my comparison image of all the BST Starguiders (Paradigms) stacked up against the Meade HD-60s (discontinued) and a table of measured dimensions.  If you click on the through the eyepiece image and enlarge it, you can get some idea of the edge falloff in sharpness of each eyepiece.

1 hour ago, Ricochet said:

Only the smaller 100p base has a thread for tripod mounting. Fitting the larger bases to a tripod requires some modification. 

That's a pity they didn't think to include that nifty feature on the 150p.  That leaves the user with either using the dovetail rail in a clamp head of some sort:

or remounting the entire base on a wide tripod top:

Doesn't it have a 3/8" threaded hole in the bottom of the azimuth axis?  If so, you can just thread it onto a 3/8" photo tripod stud or adapt a different type of tripod to 3/8".

The 25mm BST performance is well below that of the 8mm and 15mm version.  However, anything that performs better at 60 degrees around 24mm to 25mm is much more expensive.

I sometimes use my GSO 2" ED Barlow with a TV PBI to eliminate exit pupil issues and hard vignetting for the whole night just to change things up.  It allows me to use my 2" eyepieces like the 40mm Meade 5000 SWA, 40mm Pentax XW, 30mm APM UFF, 30mm ES-82, 26mm Meade MWA, 22mm Nagler T4, and 12mm & 17mm ES-92 eyepieces at higher powers.  They provide a different experience compared to my normal 1.25" eyepieces in the 6mm to 20mm range.  Longer eye relief, wider apparent field of view, etc.  Otherwise, I rarely use any Barlow, 2" or 1.25", except to reach focus with my binoviewer.

I just use a plastic, stacking patio chair for most of my observing.  It's convenient because it's already out on the back patio, so one less thing to haul out.  When my back gets tired, I can lean back, unlike most dedicated observing chairs.

I've got a SVBONY 20mm 68° on the way.  I'll give it my usual testing and observing runs as time allows.  I'll see how it stacks up against my other 18mm to 22mm eyepieces.  I'm hoping it might work as a pair in my binoviewer if it isn't that great monovision-wise.

Next time, try tapping on the edge of the sun on your phone's screen to get it to focus on the sun rather than on the eyepiece.

6 hours ago, Don Pensack said:

As for a dedicated single vision pair of glasses for astronomy, I'm with Louis.  There's just one problem: I cannot then read my notes or the screen of my DSC.

I have presbyopia too, so I cannot see anything near without strong correction.  So I got a pair of large lensed glasses and had them made as bifocals with only a very small bifocal section at the bottom.

I got "lucky" I guess because my eyes are fixed focus at about 8 inches, so I can generally read notes by simply looking under my specs.  My wife is like you in that she had to get bifocal computer glasses for work so she can read her monitors at 2+ feet and documents at around one foot.  My astigmatism doesn't bother me too much when reading for brief periods of time, as at a telescope.

The Mak is the much better deal of the two.  The Newtonian seller wants new pricing for used equipment while the Mak seller is applying a proper discount against the new price.

The Mak will also have much better resale value down the road.  Those cheap Newts don't hold their value at all.

2 hours ago, johnturley said:

I can't understand why Tele Vue decided to discontinue their 26mm Nagler, leaving a large gap between the 22mm and the 31mm.

They probably ran out their existing stock and decided that it wouldn't be economical to start another run given past sales performance.  They would also probably have to raise the price as well to cover new, higher manufacturing costs to such a point it probably wouldn't be at all competitive.

2 hours ago, W0nderste said:

Hi Louis, 

i really appreciate the reply, although I'm not really sure I understand it.

so my right eye cylinder is 3.25 (that's my good eye...lol) so according to the chart I will see astigmatism in pretty much all EP's.  
but how does that manifest itself viewing as haven't really noticed anything specific

Mostly you'll see spiky stars instead of round stars no matter how much you try to bring it to best focus.  The spikes also rotate with your head if you pivot it around the axis of the eyepiece.  This same effect also blurs low contrast details on planets and makes resolving globular clusters difficult.

To see the effect for yourself, try looking through an eyepiece at a well focused, bright star with either eye without glasses (may need refocusing between eyes), and then repeat the experiment after refocusing while wearing your eyeglasses.  At 3.25 diopters of cylinder, you should see a dramatic improvement in the appearance of stars with eyeglasses.

For us astigmatism sufferers, I recommend sticking with longer eye relief eyepieces and buying a dedicated pair of distance-only eyeglasses with low index plastic lenses (to reduce off axis chromatism) for astronomy.  Daily wear glasses get thousands of tiny scratches in the lenses that manifest themselves when viewing stars in my experience.  Keeping a dedicated, low-scratches pair around is really helpful.  When viewing with ultrawide field eyepieces, single vision lenses are also superior to bifocal or multifocal lenses because all parts of the field are in focus at the same time.

In the US, I've had very good luck with EyeBuyDirect buying low cost, online, single vision eyeglasses.  I'm sure there's a reputable UK equivalent.

I would recommend the 35mm Aero ED for a widest field eyepiece in that scope.  I believe TS-Optics has it in stock as the UFL based on a recent post here on SGL.

1 hour ago, W0nderste said:

i do have an astigmatism prescription but I don't wear my glasses for observing and have no idea how astigmatism effects viewing and/or how much 'eye relief' is best.

It's based on exit pupil which is the eyepiece focal length divided by the telescope's focal ratio, and diopters of cylinder correction on your prescription.

Tele Vue's Dioptrx page has a nice diagram for estimating when you'll need correction based on exit pupil and number of diopters of cylinder (astigmatism) correction that I've repeated below:

The upshot is that if you have mild (0.5 diopters or less) astigmatism, you probably won't notice it except at the largest exit pupils when working at low powers with smaller f-ratio scopes.  If you have strong astigmatism (2 diopters or more like I do), you'll probably need to wear your eyeglasses or use a Dioptrx at all but the very smallest exit pupils when working at very high powers.

1 hour ago, W0nderste said:

Out of interest, how do you take the pic of rulers.  I assume that is an indication of the apparent field of view or something?

It's fully described in my original images thread in two posts.

1 hour ago, W0nderste said:

Are these all the versions of APM?

All are optically the same internally with different barrel designs outside.  I've also read that some of the heavier versions (e.g., Altair) use a stainless steel barrel instead of aluminum like the APM.

8 hours ago, Geoff Lister said:

you have obstructed views, there is a manual alignment option

That's my situation since my trees matured.  I have a sliver of sky about 20 degrees wide to the south and overhead that are clear.  The rest is either partially or completely obscured.  Two star aligning my DSCs is a real chore because of this.  I'm lucky if I can see one bright star at any given time.  That's why I really like SkEye since it requires no initial alignment.  I then refine alignment on objects that are visible.  It's been helpful in getting my bearings when I can't see an entire constellation or group of them.

As far as 1.25" eyepieces in that range, I have the 24mm APM UFF, 25mm Meade HD-60, 25mm BST Starguider (Paradigm), 23mm Aspheric 62°, etc.  I'm assuming you're wanting to stay within 1.25" eyepieces.  The 24mm ES-68 is also well thought of as is the 24mm Panoptic, but neither have enough eye relief for me.

1. Do you need long eye relief for astigmatism in your observing eye?
2. What is your budget?

Below are some of my eyepieces in that range imaged through an AT72ED similar to yours:

The Meade MWA is really a 25mm, so it fits your criterion if 2" is okay and you can find one.  They've been discontinued along with the HD-60 series.

7 hours ago, Geoff Lister said:

The camera is a 640 x 480 pixel device, similar to a basic webcam, and needs fairly dark skies to "see" enough stars to perform its plate solving.

So, if you're way north in the summer, you can forget about this technology working during the "night".

On 23/05/2021 at 18:36, Klukdog said:

She has expressed a desire to own a telescope.

For what purpose?  Surely she has expressed an interest in using it either visually or photographically.  Any idea which way she leans on usage?  Hopefully not just as a piece of interior decor.