Louis D

6 hours ago, Mark at Beaufort said:

Martin I always worry about cheap solar filters so I agree with discardedastro above. My reasons for being worried is a work colleague's daughter went to see the Total Eclipse and was given 'proper' eye glasses. She has lost her sight.

I bought solar eyeglasses direct from Thousand Oaks to ensure I received genuinely safe filtration for my family.  I am so horrified by your story.  My heart goes out to her.

On 20/02/2021 at 11:10, Deadlake said:

@jetstream Gerry told me similar to Nagler 31 mm but lighter (Sure I’ll get corrected if wrong model) but lighter and not much difference. Hence I went with the APM, I don’t have Gerry’s dark skies.

Back to OP's original query, have you received your 30mm APM UFF?

You'll need a field derotator for DSO photography with an alt-az goto mount.  Alternatively, you can stack lots of much shorter exposures.  I believe there's a thread on SGL covering this technique.

Another alternative is electronically assisted observing using night vision technology.

Thanks for confirming my suspicions.  Due to trees and buildings, I have very limited low elevation viewing options from my backyard.  I'll probably get the Lunt for visual instead.

On 21/01/2021 at 06:27, Rusted said:

The Lacerta has a Brewster Angle layout. Which is not as comfortable to use as a 90° wedge. No problem for imaging but not ideal visually.
I have the 2" Lacerta and a 1.25" Lunt so have experience with both.

On 22/01/2021 at 01:27, Rusted said:

The Lacerta suits winter observing where there is plenty of room for the observer.

It does NOT suit higher solar altitudes, on foolishly long telescopes, in foolishly undersized [3m/10'] observatories. 

I just realized that using the Lacerta in summer at 30 degree north latitude where I live would be a nightmare of contortions to view the image.  Correct me if I'm wrong, but at solar noon on the summer solstice, the sun will be at 90 - (30 - 23) = 90 - 7 = 83 degrees elevation for me.  Given the Brewster angle of 56.6 degrees for the Lacerta wedge, this places the eyepiece at a angle of (90 - 83 - (90 - 56.6)) = 7 - 33.4 = -26.4 degrees.  That is 26 degrees below horizontal.  Am I missing something here?  The Lacerta wedge would only be useful for me for when the sun is no more than 56.6 degrees in elevation.  This eliminates viewing for quite a few hours around solar noon during the late spring to early fall months.

Is the Lacerta wedge that much better than using two linear polarizers in the Lunt to justify the contortions?

Deleted duplicate posting

On 26/02/2021 at 05:12, Skygazerlass said:

took 3 hours to get there and back but it was worth the trip lol

It must be a US/UK thing, but when I was going into the office pre-Covid, I drove 1 to 1.25 hours each way each day, so driving 1.5 hours each way to pick up a scope is not a big deal at all.

4 hours ago, Philip R said:

Bear in mind that some zoom e/p's, the higher the magnification the narrower the field of view.

Actually, it's the opposite in pretty much all zoom eyepieces.  The apparent field of view (AFOV) narrows considerably at lower powers, necessitating a separate widest field eyepiece such as a 32mm Plossl or 24mm superwide.  At higher powers, most zooms have nicely wide AFOVs.

Looks like you both need a Sony E-mount T-ring adapter.  They're available from multiple vendors.

You'll want to budget for an all weather cover if you're going to leave it outside.  I would just get an 8" Dob and have the kids download SkEye app or similar to their phone(s) to help them learn the night sky in real-time.  If the 8" Dob blows over in a gale, it's not likely to be damaged like a scope up high on a tripod.  That, and they're so bottom heavy they're less likely to get blown over.  With eyepieces that you'd want to bring inside when not in use, you should be able to come in well under £1000.  The problem is lack of astro stock right now.  It's been dribbling in from China, so get on several waiting lists to hedge your bets.

Also, make sure to put some sort of paver blocks under the scope.  The Dob base's MDF board warps when in contact with wet ground or grass.

25 minutes ago, Thalestris24 said:

Well, at least it wasn't a complete waste - I'll have to try it on some dso's, if I get the chance.

Louise

I've blown $15 on far more ill-advised purchases.  For example, I still have an Orion flexible red/white astro flashlight from the late 90s that quickly broke.  The switchable red filter in front of the bulb won't move into position rendering it useless at night.  I should have chucked it 20 years ago, but I had spent a decent chunk of change on it back then, so I couldn't bring myself to do it.

1 hour ago, Thalestris24 said:

Had a good view of the Moon with the aspheric on my 115mm/f6.95 frac and 2x Barlow  Shame I don't have my phone adapter yet! Should come next week, hopefully.

Louise

They really shine in binoviewers for max field for those of us with wide nose bridges and deep eye sockets thanks to their diminutive size.  Since I generally use a 3x equivalent Barlow to reach focus, they are great across the field in my refractors and Dob.  Their light weight is also most welcomed in this usage to ease balance issues.

On 24/02/2021 at 12:40, vlaiv said:

Here is simple method of doing it (at least I think it is simple).

Requires way to measure distance and white circle on black background.

Test is conducted by standing in front of the wall with circle on it at some distance so that circle is approximately the size of quoted FOV. Now take eyepiece and place it in front of one of your eyes - as if you are observing thru it. You should see field stop of the eyepiece and out of focus light in FOV. Keep you other eye open and move forward/backward until two circles overlap.

Measure distance from your eye to circle on the wall and use diameter of circle to calculate angular diameter of circle at that distance.

This technique can be used to compare fields of view of two eyepieces. You don't need circle - just a blank white wall or any other background that will illuminate FOV properly. Place each eyepiece on respective eye like when binoviewing. You should be able to instantly tell which FOV is bigger since circles will overlap but have different sizes (or same size if FOVs are equal).

I use the projection method followed by trigonometric calculations to get each eyepiece's AFOV to within a degree or so accuracy.

Once I have a baseline of reliable values for eyepieces within a given AFOV range, I can then use comparative analysis of my images of the AFOV to further refine the values within a group.  I divide the width in pixels of the most accurately known AFOV by two to get the opposite side value, accept the half angle from the projection method as accurate for the subtended angle, and then back-calculate the virtual distance to the image circle to get the adjacent side value.  I then use this virtual distance as constant across images and use the half-widths of the other AFOV images to calculate their half-angles for AFOV.  The AFOV calculations are accurate within the group.  Whether the AFOV values are absolutely accurate depends on the accuracy of the original eyepiece chosen as having a well known and measured AFOV.  That's how I got the values for my 26mm Meade MWA report.  Projection methods failed utterly with its massive SAEP.  There was no good way to measure the value via projection accurately for both full field with raging SAEP and easily seen field with minimal SAEP.  The main problem was the very indistinct exit pupil point that covers 12mm of distance according to Ernest in Russia.  This made measuring the adjacent value difficult.  Ernest made no attempt to measure the easily seen AFOV in his review that I could discern.

I put a cut-down foam bicycle grip over my 127 Mak's focuser shaft since the original plastic grip split and fell off.  I had to build up the shaft diameter with racquet handle grip tape first.  It works great and just fits next to its 2" visual back.

I recommend becoming proficient using the scope on your own before bringing your daughter outside.  On the other hand, kids learn quickly, and she may take to using the scope quicker and easier than you.

It's a beginner scope which means it has crude movements, basic eyepieces, and a compromised viewing position due to the included 45 degree diagonal.  It's actually easier to get started with an advanced scope and eyepieces in my experience because the equipment gets out of the way, and you can concentrate on learning the sky and honing your observing skills.  Imagine if you had to learn to drive on a Ford Model T as compared to a modern vehicle.  You'd have to be constantly aware of the older vehicle's crude mechanicals instead of concentrating on the road.

The Hyades and Collinder 70 in Orion's belt are also good bin targets this time of year.  Also, pan around between Casseiopia and Perseus before they set.  There are a bunch of beautiful open clusters in that area as well.

13 minutes ago, Thalestris24 said:

Just a quick update. I received the aspheric EP today but it wasn't any good - wasted my money  I think, after all that, I'll just get another couple of the 25mm EDs.

Thanks all for the suggestions and data

Louise

Sorry to hear that.  Mine have been excellent in binoviewers.  Perhaps they have gone down hill in quality over the last few years, or they are simply incompatible with the light cone of a microscope.

37 minutes ago, Thingo said:

Why not use the barlow for the 31 mm though?

Because you need to use a telecentric magnifier like a Powermate at long focal lengths (above 20mm or so) to avoid vignetting and pushing out the exit pupil causing blackout issues.  This then leads to a very long and heavy moment arm in the focuser/diagonal which can be difficult to balance in an alt-az mount at high altitudes.  You're generally better off to buy a comparably compact and lighter 13mm to 16mm 82 to 100 degree eyepiece instead.

If the Ethos are too expensive, you might want to investigate the 100/110 degree eyepieces marketed as APM/Myriad/Stellarview/WO/Lunt/etc.  They've been getting very good reviews at reasonable prices.

Before you rush off and think all Naglers are parfocal, look at column F under eyepiece dimensions of the Tele Vue eyepiece specifications page.  Notice that the 31mm NT5 is parfocal with the 21mm and 17mm Ethos and nothing else.

I would also investigate the Morpheus line of eyepieces.  They're nearly as wide as the ES-82 and Naglers, have longer eye relief, and are very well corrected at f/7.7.  I have the 9mm and 14mm versions.  The 9mm is pretty close to being an equal of my 10mm Delos.  The 14mm falls a bit behind at the edges, but probably no worse than a 14mm ES-82.

Are you using a tracking mount?  If so, you may be able to get by with narrower fields of view at higher powers since planets, PNs, and double stars tend to be quite small.

5 hours ago, adictd2dalite said:

I think these could be from the 60s or 70s and perhaps made by Towa for Swift Optics but I'd like to know more.

The circle-T mark means Tani optical house.  They were best known for their volcano top orthoscopics sold through University Optics, Kokusai Kohki, and many others.

8 hours ago, balticsensor said:

Well, there is a very slight image degradation near the very last 3-5% of the image circle.

Not unusual right at the field stop for the best eyepieces.  You can put a bright star out there and rack focus back and forth to check for aberrations.  If it switches between being a radial line and a tangential line on either side of best focus, that's astigmatism.  If the star is simply stretched into a radial spectrum of colors at best focus, that's chromatic aberration.  If it needs to be refocused between the axis and the edge, that's field curvature (which could be in the scope as well).  If it simply expands into a teardrop shape pointing to the center even at best focus, that's coma (again, could be in the scope).

On 02/02/2021 at 13:41, Tiny Clanger said:

You could keep a look out for something like a Manfrotto 55 series tripod  , or a 190 (slightly less carrying capacity, think that one is about 7kg from memory ) going cheap secondhand locally ... you only need the leg section, so may get a bargain as most photographers would rather buy one with a suitable photo head included in the deal.

I use Bogen 3036 tripods under my alt-az heads.  They are now known as Manfrotto 475B and are much more expensive.  Used Bogen 3036 tripods with heads can be had for under $150 shipped within the US.  They are super sturdy in my experience.  It might be worth checking around for them.  The Manfrotto 058B (Bogen 3051) is basically the same with different leg locks and can be had used for under $200 as well.  I like the variable angles for the legs so I can set the height and level without extending the legs.  The extendable center column is also handy for use with refractors when moving from zenith to lower altitude objects.

On 20/02/2021 at 17:06, Jasonb said:

Why do EQ mounts have counter weights and AZ mounts don't, or is that an accurate statement?

Most GEM EQ mounts don't have the ability to overcome the weight imbalance without counterweights.  There are some harmonic drives that don't need counterweights up to a certain point.  They employ a drive technology similar to some assembly line robots, and you never see counterweights on them.  Some direct drive EQ mounts are also able to handle imbalance as well.

As long as an alt-az mount is level and the entire load is well within the footprint of the tripod, counterweights are generally unnecessary.  However, if you set up one tilted, as on a slope, the azimuth axis will swing around by itself until the load is at the lowest point.  If it was properly counterweighted, this wouldn't happen.  However, it would weigh a lot more and be much less portable to dodge obstructions such as buildings, trees, and shrubbery.

On 23/02/2021 at 04:00, NorfolkGazer said:

This is the start of my modest collection. Housing the Telrad and my modified liveCam up to now. I'm not putting the 'stock' EP's that came with the scope, rather waiting for when I replace them with the BST SkyGuiders, the first two of which should arrive next week. 

 

My Telrad got kicked out of my A-team case years ago in favor of more Pentax XWs.  I just put the pick-n-pluck foam blocks I'd saved back in.  They stay in place due to friction.

My Telrads now live in a cardboard box wrapped in closed cell foam padding.  They're surprisingly rugged.

2 hours ago, Carl Au said:

I bought a Starwave from Altair about a month, optically the best scope I ever owned

They look to be Sharpstar Optics made scopes based on the mechanicals.  I have one of theirs as a TS-Optics 90mm FPL-53 triplet.  I love the mechanicals as much as the optics.  For instance, I've come to the conclusion from using it that every frac should have a camera rotator at the end of the focuser to safely and smoothly rotate a heavily loaded diagonal to the side.  I prefer it to rotating the whole tube in the rings, rotating the focuser only, or simply loosening the diagonal and rotating it.  The focuser is buttery smooth.  The optics are impeccable as well.  SO seems to be positioning itself as a premium telescope maker.