jetstream

1 hour ago, faulksy said:

get the sips. no settings needed, every ep is the same 😀

no SIPS.... just bought the Paracorr II, which I can easily switch to the 15". Speaking of which I'm putting encoders on that one too and I'm trying to get silicone cold temp cables.

2 hours ago, faulksy said:

@jetstream im surprized you don't like the pentax xw range Gerry, ortho with 70*

I just might own one soon Mike! What settings do they use with the Paracorr?

Well, a new Televue OIII for the 15" is on its way, but will be tested on a spectrograph by a good acquaintance and scope maker first. Good deal really- if it doesn't give good numbers back it goes- before its sent to me. If fit passes, the new Nebustar will go through the same paces.

The 17.3mm and 10mm made it today- next week for the adapters and 8mm Delos. This is a good sale IMHO and I might try a Televue OIII next.

5 hours ago, Captain Magenta said:

A read of Harold Suiter's "Star Testing Astronomical Telescopes" gives a very good guide through all of this, in some detail but not too text-book. And much much more besides, including a great section on Newtonian Collimation.

I like the MTF graphs in the book- they visually show the interesting effects of central obstruction, thermals, optical quality and seeing. Another  good source is Peach's article

http://www.damianpeach.com/simulation.htm

18 hours ago, vlaiv said:

This is debatable, and it depends on technique used to asses wavefront. If interferometer is used then yes, it should include image, but interferometer is not always needed to determine above.

I like an actual picture as it is a quick, easily understood thing without the need for technical expertise. Crooked lines bad-straight ones good lol!

Anyway, the most important thing in all this is finding and using an honest trusted optician for the tests IMHO. Some of the best don't provide their test numbers ie Lockwood, but he will not sell a poor mirror only top ones.

If there is a dispute an interferogram picture is pretty hard to dispute compared to the computer generated representation of it and all the numbers including RMS and Strehl which uses the RMS to calculate.

All the numbers should be in line with each other (and picture) IMHO- except the PV... I'll take a 1/5 wave PV .92 Strehl with honest numbers over the many encountered 1/10 PV .98+ Strehl some makers put out any day.

A true "1/4 wave" system actually gives very good views IMHO.

I do appreciate your technical posts as I do gather more insight from them Vlaiv- thanks, Gerry

38 minutes ago, Rob Sellent said:

and was wondering what it is I should be 'reading' and what it is those figures/colour images are telling me?

Mr Rohr is VG and is a trusted source.

First thing, you have selected test reports done in 2 different wavelengths, they all need to be checked as results can vary color to color- espc doublets IMHO -s there a blue test result?

Anyway, a top optician explained how to read an interferogram very simply- the lines should be straight. Also the best test report includes a sample of the many actual pictures, not just computer generated synthetic interferogram images.

PV is the least of my concern if the RMS and Strehl are good.

One thing I always ask for is a truly smooth mirror, something that is not on the forefront of discussion necessarily. These 2 top refractors will perform very good I would imagine- and Canon makes very smooth, top quality lenses IMHO.

1 hour ago, Ships and Stars said:

from Eyebrow, Saskatchewan

lol! I was just very near there on a road trip- the vast expanse of the prairies is hard to comprehend unless seen. Nothing like a prairie wind... to frost your......😀  I used to work with a bunch of guys from Labrador City, came here when there were mine issues there, good guys the "newfies are"!

Yes -30c or worse starts to "bite" if you know what I mean and it shows up all kinds of flaws in the scopes- dobs by far work the best and having a couple of favorite EP's  in the same fl help when one frosts up. I can tell you this -ES eyepieces are very tough- I tested the seals going from -30c frosted up by running warm water over the whole EP and the 30ES 82 passed with flying colors. Zero problems and zero internal fogging.

Yes, try to find a chunk of property some where for a cabin, you will love it!

Gerry, from the land of ice and snow.

1 hour ago, Ships and Stars said:

I struggle living in towns

I see we share a common thing- I moved from a town to a dark place on a lake 5 years ago, in NW Ontario. There are so many more opportunities to observe, if its clear wheel the dob out (cooled) and start observing within 10 min even with the 24".

Maybe there is a smaller parcel around there you can pick up?

BTW our coldest temp last year, no wind was -42c. My very best views are in a cold front after a snowstorm.

11 minutes ago, Piero said:

Great stuff, Gerry!

Hope you find the push fix adapter as useful as I do!

Thanks again Piero, it should be here in a couple of weeks. This adapter should allow the "A" setting on the PCII or allow me to shim it so it does.

I'm trying to get all my eyepieces to work on "A" or "D" for ease of use.

35 minutes ago, scarp15 said:

Are there particular targets you plan on using these for Gerry?

Yes, there are some targets in mind. The Delos series are very deep widefields and with high DSO contrast. The 17.3mm will be a galaxy finder and then then 10mm and 8mm will be used to pull really faint ones out, possibly close to top ortho levels, not quite but close. My former Delos were deeper and with much less scatter than my Ethos. I do love the immersive view the Ethos gives however.

Another target will be planetaries- after viewing that sharp annular ring in the Blue Snowball last night I figured a bit more comfort would be nice and with less lens fogging in the cold compared to my orthos, the 20mm eyerelief will be good to have.

Actually I'll use these Delos for everything- lunar/planetary/nebs and galaxies.

I've just suffered a moment of weakness and ordered the 17.3,10 and 8mm Delos... also incoming is the TV intravel adapter and a Baader Pushfix adapter @Piero thanks for the Docter saving adapter info.

The TV sale is a nice discount so I figured now is the time (to move into the Seacan lol!)

2 hours ago, Ships and Stars said:

I have a 200p on EQ5, that would be amazing if I could bag the HH from my 21.9 site!

I was really close here from home with the 20" but the LP is just a bit too much.

Desperate for some clear skies now but as I mention in my other post, not holding breath, forecast is Grim with a capital 'G'.

I did see a few stars last night through some clear patches, so hopefully the forecast is just wrong...

What f ratio is the 200mm? Ive seen IC434 with my 200mm f3.8 but in this scope I'm looking for a tiny pimple of a HH notch. The extra FOV the shorter fl scopes give is not our friend for the HH IMHO, Alnitak is pretty bright.

There is no question in my mind the 200mm f6 newts will show it with the right combination- which means stray light control among other things.

7 minutes ago, Littleguy80 said:

Thanks Gerry. I was thinking of starting with the APM 20mm and Hb and experimenting from there. I have the TV 25mm Plossl and then the ES82 30mm if I feel I need more exit pupil. I hadn’t considered the UHC so that’s a very helpful tip. I should have remembered that from the Flaming Star neb last winter. Which UHC filter do you use? I’ve only ever used Astronomik‘s in both 1.25” and 2”. I’ve not tried other brands so I can only say that it seems to work well when used with the right targets. 

I lucked out a few years ago and got excellent copies of Lumicons OIII and UHC, both top notch. Later on, with the company in transition or whatever I did not luck out and paid big money for a sub par Lumicon 2" Hb...

You will see the Cocoon for sure with your 10"/20 APM/Hb if conditions allow.

@quaoar Very nice binoscope! I bet the views through it are jaw dropping.

5 hours ago, Littleguy80 said:

Excellent report, Gerry. I observed the little Dumbell through our clubs 12” dob. It had little “hooks” of nebulosity that appeared almost like spiral arms of a galaxy. I’d never seen that feature of M76 before. It was very neat. 

I’ve been thinking about having a go at the Cocoon this season. Do you have any experience with your 10”?

Thanks Neil it was great to observe again. The Cocoon... it is actually a hard object and I've used the 1.25" Hb with success on it in the 10" as well as the UHC.  Some say the Hb is the preferred filter to detect it and in the 10" it will appear as a small hazy glow at the end of a long dark neb- but the filters escp the Hb hurt the dark lane.

I cheated ....I used the Sky Commander and it put me right on it lol!

M76 is great! Love those hooks and the 17E/UHC really made this one strut its stuff.

Whats your plan for filters and eyepieces? A good tight UHC offers more mag range IMHO than an Hb.

Finally a half decent night to observe, avg trans with SQM going 21.6 and M33 teased me flicking in and out a few times naked eye. Scope: 24" f4.1 dob/21E,17E,10BCO/PCII Lumicon UHC.

Speaking of M33 is showed another spiral arm easily tonight in addition to the dual skewed arms, a great nice sight.

@Ships and Stars , I wanted to give you a heads up on the Wizard nebula- it was really easy tonight and distinct with the 21E/Lumicon UHC. The "left" side (in EP) showed as a roughly triangular patch of nebulosity mixed in with a bunch of stars- in the middle a Vg dark rift, almost funnel like followed by a large patch of nebulosity drifting up and to the right. The 21E was used with the Paracorr II and the Wizard fit the FOV very well. You will see this object no question with your 20".

As well as the underwhelming Cocoon neb which did show a bit of structure with the UHC.

A real prize tonight was seeing the Blue Snowball, NGC 7662, actually the prize was the bright, sharp, not quite complete annular ring- fantastic! and what color!The 10 BCO/PCII brought this to life.

So much more...M31 gave up more dust lanes just "above" the bright, hazy glob near the one end, well worth trying to see. Tonight with the 21E/PCII the structure showed well and easily.

The fantastic Little Dumbell, M76 is a show case object, I'm really getting into planetaries these days.

All in all a pretty dang good night!

7 hours ago, Ships and Stars said:

SGL could host a cheapest ep and scope /Horse Head competition, with handicap ratings for different Bortle conditions! 

lol! I agree- my Vx10/Super 25 showed it and I'm positive a SW 200mm f6 dob would show it too, with the appropriate EP, maybe the vg 30mm Sterling plossl. A top Hb is needed though IMHO.

Your 20" will show the HH with no filter- my 15" does, with the UHC too.

One of the many reasons I chose the Astrosystems truss dobs is the filter slide. I looked around years ago for the slides with varying degrees of success. Some are no longer made, but checking around might reveal results.

Also, my latest purchase was a Paracorr II, I hemmed and hawed for a long time but it works very well and might be something for you down the road. Its works well enough I might go back to Delos for a great, low scatter, high contrast option that is easy to use in the PC. Astronomik make excellent filters.

Of course all this top stuff is nice but not needed to get excellent views IMHO... the SW 25 Super Plossl shows the HH for example,easily.

On 18/11/2019 at 14:39, Captain Magenta said:

Up to 5mm of movement at the primary

Not good, but nice catch. I found out playing around that unless there is a bunch of focuser slop, that drawtube flexure only affects sec collimation when racked out and with a hvy weight.

I cannot use binoviewers in my VX10 because of tube flexure and in the 15" with a Moonlight collimation stays steady until over 1/2 racked out with the Binotron 27's.

Obviously your spider vanes are tight? Sometimes they can loosen up from pulling the tube in.

5 hours ago, Ships and Stars said:

The Orion Ultrablock seems to get good reviews, though I've not tried it. 

 

IMHO forget this filter, mine was a piece of junk that I chucked in the waste bin. The newest Astronomiks should be VG and I would seriously consider the new Televue filters rumored to be made by Astronomik to their specs. I have an older Lumicon UHC/OIII which are top notch but I would avoid the new ones. The Astrosystems dobs that I have include a filter slide which is fantastic and work with the Paracorr. Filter slides are well worth considering.

Its been raining/snowing/cloudy for a year here pretty much, I truly miss observing. You have some great skies available so take advantage of them as much as you can.

Eagerly waiting your Horse Head report with the 1.25" Astronomik Hb (same as mine) using a nice TV plossl! This will be a piece of cake for you if you keep scatter under control.

15 hours ago, Ships and Stars said:

Excellent Stu. This sounds perfect. I didn't realise the Wizard Nebula, for example, was something like 25' across and quite faint to boot.

I'll definitely study these links, many thanks!

Great report S&S, I have observed the Wizard in a different scopes- A few nights I followed nebulosity from the NAN all the way up into Cepheus, almost continuosly . The 200mm f3.8 newt is excellent for this but the bigger scopes will show these objects too. Its a good idea to start looking for shade edges with the bigger ones.

Most all my nebula observing these days involves the 20mm Lunt or 21E across the scopes (newts). Once you start seeing all this it starts to get hard to identify them, I think there might be some DSC that can help in this regard.

Your 20" under dark skies will show objects at the limit of most charts- and beyond. Try a tight, high transmission UHC from very dark skies...

At f6 it should look something more like this

4 hours ago, Deisler said:

This was the pic I took with my phone when I collimated it a week ago. Checked last night - it remained the same.

I might humbly suggest that your collimation doesn't seem right, it is an iterative process, back and forth from sec alignment to primary etc. I collimate with everything from a cheap effective Celestron Cheshire to more expensive tools.

Part of your eyepiece issues may be related to collimation.

5 hours ago, Deisler said:

I spent 30 mins or so, trying to find Andromeda galaxy - to my disappointment I did not manage to see it

You most likely did see it- trying more magnification on M31 could help. Also what do you collimate with?