John

StellaMira Losmandy plate for use on my 130mm triplet refractor. Lovely quality item. It sits really nicely and securely in the ADM clamp on the T-Rex mount.

Just got to bolt it to the tube rings on the scope now.

Many thanks @HollyHound

The "window" of visibility is quite short between the time it rises and when dawning light overcomes it. It's not a daylight comet yet !

55 minutes ago, Louis D said:

What I'm wondering is how the Pentax XW 40mm stacks up against the Meade 5000 SWA 40mm that I've been using since the great SWA blowout sale.  I picked it up for $125 and am wondering how much better the $400 Pentax 40mm would be.

I wonder how the Aero ED 40 would do compared to the XW 40mm ?

I picked up my Aero 40 (well a clone of it) for peanuts really but it's proved a good performer even with my F/5.3 dobsonian.

Unless someone lends me an XW40 I'm not going to find out. I'm not going to risk $400 for an eyepiece that won't get lot of use.

I feel a little for the folks who paid big prices for the 2 inch XW's during the period when they were out of production. I saw silly prices being asked for the XW 30 and 40 at one time - substantially more than they cost new now.

3 hours ago, johninderby said:

Glad ypu got it sorted but why oh why don’t they provide a drawing with measurements in the first place. 🤔

There is a photo with measurements on FLO's site but the measurements are not the ones that are really needed - the centre to centre distance between the mounting holes !

Glad you got it sorted anyway Steve

Clouded NE horizon here at 3:00 am so went back to bed. Still cloudy when I woke again so no go here today.

Good to hear that others are getting sightings in though

It might not be Hale-Bopp II but it's the best over the past 7 years apparently so well worth discussion and reporting IMHO. Also you never quite know what it's going to do next ......

I bought a WO DT bar last year from that range and it turned out to be slightly narrower than my other Vixen type bars. The ADM clamp would not grasp it firmly. Not really what was wanted !

FLO did their usual quick return though.

Why can't manufacturers stick to an accepted standard, at least when it comes to mounting arrangements

You need holes at 35mm centres for the Skytee II and many other alt az mounts. Looking at the WO diagram (blue image on FLO's page) it is difficult to see if it has that

See if you can find the "disperse clouds" function. I'm going to need it if I'm going to see comet Neowise again this morning

Hi,

I think your 130 Astromaster should do quite a lot better on the moon and planets than the 90mm F/5.5 refractor will.

The 90mm F/5.5 achromat refractor will produce quite a lot of chromatic aberration which limits its usefulness at high powers.

The 130mm Astromaster F/5 newtonian optics gather much more light, have better resolution and are apochromatic so do not have issues with chromatic aberration.

If you want a refractor that is good for the moon and planets you need to look at something around 102mm and with a focal length of around 1000mm so F/9.8 or F/10.

Orthoscopic is a set of characteristics rather than an optical design I believe. Maybe thats where Vixen were coming from ?

TMB called their Paragon  superwide eyepieces "Orthoscopic". Today I understand that the same optical layout is found in the Aero ED range and clones.

I found a shorter focal length eyepiece with a wider AFoV showed as much sky and a darker background sky when I had an 8 inch SCT. I preferred a 40mm 68 degrees to 50mm for this reason.

1 minute ago, goodricke1 said:

Lot of comments for a barely naked-eye object... imagine if this place had been around during Hale-Bopp! 😇

Quite a lot of comments when a small sunspot group appears as well.

We are an astro forum - what are we supposed to discuss ?

Clouded over here for now. Quite thin stuff though.

I agree with Neil / @Littleguy80 above. Last night was too cloudy to observe but there were enough breaks in the right place (for a change !) to see the comet when the time came.

Don't need a scope set up either - 70mm binoculars should show it very well and are very "grab and go"

I've owned lots of Tele Vue plossls (both the earlier ones and the current range) and found them very good apart from the eye relief which is rather short with the 11mm and 8mm given their inflexible rubber eye cups and a bit too long in the case of the 32mm which needs (for me at least) the eye guard extender to make it comfortable to use. Most of my use of these was at night.

1 minute ago, Louis D said:

I believe this shows the distance in millimeters each wavelength of light actually focuses in front of or behind the focal point as you move away from the optical axis (bottom) to the edge (top).  Thus, about 70% out from dead center to edge produces a nearly color free image when in focus.

Thanks Louis.

The number of "crossings" seems to be important. This one appears to show 4 and nearly a 5th. What is the significance of that ?

Meade 56mm plossl, if you can find it in stock anywhere:

https://www.tringastro.co.uk/meade-series-4000-super-plossl-56mm-2-11070-p.asp

GSO Superview 50mm:

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p809_GSO-Superview-2--ERFLE-50mm-Rich-Field-Eyepiece---52--Field.html

Looking possibly good here for another look at Neowise in the early hours. If I can stay awake - only got 4 hours sleep last night

Crop of one of my images from this morning:

Trouble is, 82 degrees AFoV and long eye relief don't generally go together unless the lenses within the eyepiece are massive and it then becomes a 2 inch eyepiece simply to get the support it needs in the focuser.

If you can settle for 76 degrees the eye relief moves out into more comfortable territory without the eyepiece needing to be too large and heavy.

These Orion LHD 80's apparently have long eye relief but as you can see, 9mm is the longest focal length in the 1.25" fitting:

https://uk.telescope.com/Orion-LHD-80-Degree-Lanthanum-Ultra-Wide-1252-Eyepieces/e/274.uts

The other option might be the discontinued Tele Vue Type 4 12mm Nagler which has 17mm of eye relief in a hybrid 2 inch / 1.25 inch format body.

I wish I knew how to properly interpret diagrams of this type

And this (although I can make a little sense of this one):

The above objective seems to be classed as a "super apochromat" but I'm not sure what the definition of that term is

On 05/07/2020 at 20:09, Sunnydays said:

Do you start with a lets say 32mm then switch out to the Barlow and zoom?

Sometimes yes and sometimes I go straight in with the zoom / barlow combination. Depends what I'm observing.

The good thing about a refractor obsession is that you can (generally) fit them all into the same room for a photo

Get an aperture obsession and that soon becomes difficult unless you have a really big house !

Do you think you would have the same obsession if you lived under dark skies ?

(serious question)

Software-wise I use (all free):

- Cartes-du-Ciel

- Stellarium

- Virtual Moon Atlas

- Virtual Planet Atlas

I've had a couple of versions of Starrynight but I didn't get on with those.

I have Skysafari 5 Pro on my mobile and a tablet but I don't use those devices when I'm observing. My main use for the mobile phone is occasionally snapping pics of the moon !

I've got a copy of Nortons somewhere but much prefer the S&T Pocket Sky Atlas which has become an indispensable observing tool for me.

The S&T Pocket Sky Atlas for use at the scope and Interstellarum for further reference. To my mind those two complement each other rather than compete.

I use Cartes du Ciel for comet locations and it is pretty much spot on, as it was in this case

7 minutes ago, jetstream said:

Does this design show its a pair of symmetric doublets?

What else did you think it would be Gerry ?

Most plossls are like that. The difference with the TV is that slight inward curvature on the outward facing lens surfaces. I think that was enough at that time to get a patent.

I read somewhere that Vixen use a similar figure for their NPL. Come to think of it, Vixen used a similar symmetrical design and called it an "orthoscopic" in the past.

As we know it's not just the optical design but the quality of the glass used, the figuring, polishing, coating, element mounting, baffling etc, etc etc that makes the difference.