Louis D

5 hours ago, banjaxed said:

I am not an expert by any means but in my 8” Dob an ST 120 it gives very clear images IMO

Maybe I'll pick one up sometime to try.  Does it have enough eye relief for eyeglass wearers?

As far as defocusing goes, use whichever side yields better Fresnel rings.  My APO has near textbook rings on one side and near mush on the other:

1 hour ago, pointedstick said:

Alas, my poor dad is away and doesn't get to use it with me for a month, so for now I'm enjoying it myself and with my kids.

Become the resident expert on the equipment and the sky so you can quickly get your dad up to speed upon his return.

When pondering maximum magnification, I calculate the resultant exit pupil.  Given your scope is an f/10, and 0.6mm is about the limit for small exit pupils before floaters become an issue for many folks, I'd say a 0.6mm*10=6mm eyepiece would be the absolute shortest usable focal length in your scope on most nights.  This would yield 1500/6=250x.  Rather than buy a 6mm and a 7mm eyepiece to search out your maximum usable power on any given night, I'd just buy a quality 2x Barlow for the BHZ to yield 4mm to 12mm, or there abouts.  I'll let other make currently available shorty Barlow recommendations since I don't own any.  If you come across a vintage Japanese made Celestron Ultima 2x, Parks Gold Series (GS) 2x, or Baader Triplet 2x Barlow, I can verify they are exceptional shorty Barlows.

Mars is receding away from us and is getting smaller by the day.  It was at opposition in October 2020 and won't be again until December 2022.  Other than for a few weeks on either side of opposition, Mars isn't all that great of a telescopic target.

Try defocusing a mag 2 star like Polaris once it is centered and highly magnified (the BHZ will be handy to determine the best magnification for this).  The Airy disk should show nicely concentric, smooth, round Fresnel rings on either side of best focus.

If the image shows poor collimation as on the right, you'll need to investigate SCT collimation further.  Since I don't own one and have never collimated one, I can't offer any further insights.  Just make sure the star is dead center.  Moving it off axis will make it look uncollimated.  You can defocus the star until its bloated image nears the field stop to better center it.

2 hours ago, banjaxed said:

I have an SVBony 20 mm 68 degree eyepiece which was included with a scope I bought and it is one of my favourites, it is very sharp and I could not fault it.

In what scopes?  How is center to edge sharpness and flatness of image?

If you're careful and push the cutout against two sides, that will maximize the leftover filter material in the opposite corner for a finder filter or small refractor filter.

I'd recommend getting a SVBONY IR/UV cut filter to put on your eyepiece.  I'm not convinced the filter material is doing a good job of blocking nonvisible wavelengths.  After some time observing, I get a fatigued feeling in my observing eye as if it is being cooked without the filter.  A variable polarizing filter may also come in handy to knock down the brightness a bit further if you find ND5 too bright.  I know I find it a bit too bright.

46 minutes ago, JamesF said:

Here's the video.  He's showing off, and using a C14.  Perhaps he thought a C9.25 would be too easy.

James

That still requires a dead lift of 46 pounds to a height of about 2 feet.  I can just manage that, but it leaves me with a backache.  I don't know about the OP's back situation.  Hopefully, he'll chime in with a more specific weight limit.

3 hours ago, scotty38 said:

Hi @Louis D Can I ask a question about your reports as I am not sure I fully understand them 🙂

Take the last two views, they both show the same eyepiece yet the bottom one is not as good as the one above it, why is that? I realise the bottom one says full view but if you look at the equivalent points on the rule you can see the difference so what am I missing?

 

Sorry to have taken the images out of context where I explained that.  The "Full View" are taken with a 5 MP ultrawide angle cell phone camera so I can capture the entire 70+ degree view in one image.  The regular images are taken with an 8 MP wide angle cell phone camera limited to about 70 degrees on the diagonal.   I then scale up the resolution of the 5MP image to match the linear scale at the center of the 8MP camera.  Due to magnification differences across each camera's field of view, they may not match at each point.  I capture the 8MP edge views by pointing the camera at the field stop so I have a higher resolution view out there for comparison with the center resolution image.

To summarize, there just isn't as much resolution when using a 5MP imager producing a shrunken image.  I'd love to get my hands on an affordable 24MP or more cell phone camera covering at least 110 degrees on the diagonal.

I wouldn't exactly call $55 cheap as chips.  If it were in the $25 range, I'd agree.  This eyepiece is sold under many other brands such as Apertura and Omegon, so hunt around to see if you can find any feedback or reviews of them.

Regardless, it will probably perform admirably well in an f/12 or slower Mak.  At f/8, expect some astigmatism and possibly field curvature in the outer 25% of the field.  At f/5 or slower, it will probably be a mess beyond 50%.

I have an Orion SWA Centering 20mm, 70 degree eyepiece.  Here's how it looks in an f/6, field flattened ED refractor for reference:

Not very pretty in the outer 25%, is it?  Think of it as a 20mm Plossl with more, but blurrier, outer field for context.  It will look slightly better at f/8.

11 hours ago, Goldfinger said:

I never thought about sitting in a chair but that's a terrific idea 8f I can find the right set up.

My budget is around $800.00 for everything. Telescope, lenses and some filters. What would you recommend? I'm mostly interested in the planets but willing to try my luck with DSO's. 

 

A 127 Mak on an alt-az mount is a good beginner's setup that isn't extraordinarily heavy and yet is quite capable of delivering rewarding views of most solar system objects and the brighter DSOs.  I'd definitely recommend getting a 9x50 RACI finder to go with it because the Mak's long focal length yields such a narrow field of view.  The problem right now is lack of stock.  Are you looking to buy from within the UK, US, or elsewhere?

5 hours ago, FLO said:

 

We can but we reasoned this series is designed primarily for comfortable high magnification viewing so would be most popular in shorter focal lengths.  So far, nobody has requested the two longer focal lengths but we will happily import them if enough people ask 🙂 

Steve 

That's kind of what I figured.  They're also the two weakest focal lengths in that lineup because they are positive-only designs, IIRC.  I'd probably steer people toward the BST Starguider 15mm and 18mm offerings instead.

9 hours ago, Pete Presland said:

I had a Mak180 for quite a few years, then moved to my current scope a SCT C9.25. Slightly bigger aperture (180mm v 235mm), slghtly smaller Focal length (2800mm v 2350mm). I just felt it was little bit more of an "all rounder" option. The collimation on the Mak was rock solid, the SCT is pretty good as well. Both required a decent crayford focuser due to the mirror slop when focus at high focal lengths with a camera.

It's my understanding the hoisting a C9.25 onto a mount is right at the limit for many folks with good backs, and the OP has stated he has back issues, so I would probably steer him toward a lighter solution.  I know I had to take a pass on a used 127 Mak/EQ combo from Orion because the OTA was bolted directly to the mount without a dovetail and clamp.  Along with the counterweights, it was just too punishing on my back to lift as a unit.  I didn't feel like adding and removing the weights each time I wanted to move it around the yard, so I went with an alt-az mount with the 127 Mak.  It's much easier to pick up and move as a unit to dodge trees, houses, and bushes.

2 hours ago, Gfamily said:

How accurate is your pointing when using Skeye with a 90 degree offset? Does it give you accurate 'Push to' centering on targets to within "eyepiece viewing" precision ?   

It gets me within 4 or 5 degrees of objects generally after aligning on some easy object(s) like bright planet and stars.  Sloppy by traditional DSC standards, but because it's showing me the star pattern on the screen around the object, I find it fairly simple to use either a Telrad/QuikFinder or GLP to fine tune the pointing enough to get the object within my widest field eyepiece in the main scope.  This presumes you can see stars down to about magnitude 3 or so.  Once it's centered, I realign SkEye on the object, and pointing in that region improves quite a bit.  During centering, I zoom in on the SkEye screen view to match what I'm seeing in the eyepiece.  I'm still getting familiar with it, but I've found it fairly handy so far.

It's not for the inexperienced for sure, but if you're experienced and are looking for new or difficult objects with a scope on a mount with no traditional DSCs, it's a huge help.  It much faster and more convenient than referring to a paper star chart or non-linked planetarium software on a tablet or laptop.

Another trick to try is to round off the end of the set screw with a fine file so it creates a dimple instead of a circular scratch.  Either way, you've got to really crank it down to make a mark.  Just lightly thumb tighten it, and it generally won't leave a mark.

6 hours ago, Zermelo said:

note that it does have limits on how much of a discrepancy it can deal with

I regularly force SkEye 90 degrees off the sky with it's object align function so my phone can be cradled parallel to the tube.  It seems weird that SkySafari Plus doesn't support that same functionality, or does it?

5 hours ago, Goldfinger said:

I know this sounds silly but I'm a tall guy with back issues. This one means I wouldn't have to bend as low to view.

Many folks, myself included, find seated observing much more relaxing and enjoyable.  In that case, you want a telescope mount that can be lowered enough to not have to be used with a tall observing chair.  If your back can't take being bent over at all, then that would limit you somewhat.

What is your working budget?

Many lower cost tripods use a 1/4" stud to attach the head.  Others may not be removable at all.  If it is a 1/4" stud, there is a low cost thread adapter that screws into the 3/8" hole creating a 1/4" threaded hole for the smaller stud.

3 hours ago, Stu1smartcookie said:

Did the postman bring that ? If he did , then he’s a good chap .. and I will certainly use the Royal Mail again ! Lol 😂 

Not quite postal delivery, but during the pandemic, Texas legalized alcohol to-go to help keep restaurants afloat.  It did so well, that emergency order was turned into a law by our state legislature.  Have y'all got something similar?

Isn't the internet great!  Can you imagine trying to track down one of these things without it?

Someday, you may want to upgrade to Astrodon filters.  They tend to halo the least of any filters out there.

1 hour ago, Tiny Clanger said:

It works OK,  but I prefer it on the dob base to be honest, it just seems right !

Isn't there a 3/8" thread on the bottom of the standard Dob base?  Couldn't you just screw this into the top of a Manfrotto or similar photo tripod?  That's how I attached my DSV-2B to my Manfrotto 058B tripod.  IIRC, there are grub screws on the Manfrotto underneath and around the 3/8" stud that can be screwed upward to bear against the bottom of the mount head to prevent it from unscrewing.

3 minutes ago, badhex said:

Indeed! I did a double-take when I opened the box! Note the trademark-defeating single R at the end 😉

I take it yours came from TS-Optics.  Their website images don't show the Paracor branding:

30 minutes ago, Don Pensack said:

Very few companies import the whole range.  Kudos.

I don't see the 14.5mm or 18mm focal lengths on FLO's website.

21 minutes ago, Don Pensack said:

"Paracor 35mm"???

I've seen them come up in Europe occasionally.  They're the same as the Aero ED 35mm in the UK, Titan II 35mm in the US, or Sky Rover 35mm direct from China.  I'm not sure which vendor is/was selling them labelled as Paracor, but I'll wager it's a continental European vendor.

It does seem odd to choose a name so close to Tele Vue's Paracorr.

Did we scare him off?