John

That is one of the best images of this comet that I have seen to date.

Thanks very much for posting it Ken

The challenge is that the some of the factors you list are so variable, locale to locale, hour to hour etc, that I can't see how they could be factored in for locations in the world, which the software covers

They do cater for atmospheric extinction which happens as an object moves towards the horizon and they cater approximately for the amount of daylight still in the sky. You can set your altitude about sea level. That's probably about as far as such a tool can go.

Also, an experienced eye will see more detail than an inexperienced one with the same scope. A dark adapted eye will go deeper than one that isn't. Where would you set the benchmarks ?

I see Stellarium, Cartes du Ciel etc as primarily tools to locate targets. I think what you are looking for is more of a view simulator ?

1 hour ago, Stardaze said:

..So yours John is the 1600mm FL then? 

Yes, that's the one. The widest true field I can get is about 1.7 degrees. If I want to observe the whole of the Veil Nebula I have to move to my 102mm F/6.5 refractor where I can get 4 degrees with a 6mm exit pupil.

With the 12 inch I can fit the whole of the East or West segments of the Veil in the FoV.

1 hour ago, Paz said:

..I notice they have changed the cap - they didn't used to look like that!

That's a good point. The cap on this 10mm Delos looks like the one that TV use on the 2 inch Powermate.

In the past they used a hybrid cap on their eyepieces - 2 inch one side and a touch more on the other to accommodate the eye cup.

Perhaps they have moved over to the Powermate type caps now ?

If Jupiter fills the eyepiece then it is not in sharp focus.

It will appear small in the eyepiece when it is at focus. Something like this with a 26mm eyepiece:

This is an image I got last night cropped to simulate the view that I had with my ED120 refractor at 22.5x - 3 degrees true field of view. Solid clouds and drizzle tonight. Hope the comet stays bright for a while longer

I have not measured mine but generally assume that at my age it's going to be around 6mm or so, max.

So with an F/5 scope I reckon 30-32 mm is the longest focal length that will be reasonably efficient.

I've used a 40mm eyepiece with my F/5.3 dob and don't recall seeing the secondary shadow but it would have been when viewing a dark sky so I might not have noticed it ?

I find 31mm or even better 21mm more effective in DSO observing with that scope under my skies.

The challenge with a newtonian is that the split is made but it is sometimes hard to see that it has been made due to diffraction from the secondary etc, etc.

15 minutes ago, DaveL59 said:

just saw this on the BBC new pages

https://www.bbc.co.uk/news/uk-england-wiltshire-53383007

 

Wish they would not use the headline "streaking across".

Non-astronomers will think that they have to dash outside and watch it fly over

They do qualify that in the article itself but many folks might not get past the headline and the pic.

I cool mine at around 45 degree angle with all the caps off.

Takes 30-40 minutes before I can use high powers to full effect. Low to medium powers can be used more or less straight out of the house.

4 hours ago, bomberbaz said:

Yours being the 12" OOUK dob then John I think, great mirrors. 

The one Shane pictures is / was his I think. He made an identical mount for it after he had finished mine. Mine is F/5.3.

Lumicon do make a comet filter also known as the SWAN filter:

https://www.astroshop.eu/line-filter-sets/lumicon-filters-swan-band-comet-filter-1-25-/p,6750

Whether that works with all comet types I don't know.

Great selection Shane

Each time I use my 12 inch dob, I say a little "thank you" to you

Chris Lord is a member here but has not visited for quite a few years.

I thought the central star was mag 15.3 ?

3 hours ago, Ricochet said:

I don't think it is you. I think that if you've got a 21E (which is a logical choice to achieve maximum FoV), 17mm is just too close. Maybe the idea with the Ethos focal length options is that you can choose either 21/13 or 17/10.

According to Don Pensack the Ethos range comprise 2 sequences which have logical magnification steps in most scopes:

21 - 13 - 8

17 - 10 - 6

Then you have the 4.7 and 3.7 Ethos SX

At one point I had them all but now I just have the 21-13-8-6 run with the 17mm ES 92 in between the 21 and 13.

9 minutes ago, IB20 said:

I’m in East Midlands and can start seeing it just about 10:30pm.

About the same here.

Lovely again tonight. Tried this self portrait with comet but it came out rather spooky

Glad you have seen it - it is a wonderful sight

Tonight I'm using my 102mm refractor at 17x (40mm SWA eyepiece) and it looks really splendid.

The 32mm is the best corrected of the 3 Panaview focal lengths so that is the one that I would go for. As you say, you will need a 2 inch diagonal to use the eyepiece.

3 hours ago, mikeDnight said:

Looking at the engineering that's gone into the HR body as well as the obvious high quality of the optical components, its a wonder their cost isn't much higher. It makes me love them even more.

When they go out of production their cost will be much higher !

Yes - the 130mm aperture will gather almost 4x as much light as your 70mm scope does and will have nearly twice the resolution.

The Heritage 130P is a very popular and capable scope on this forum and is owned by experienced and novice astronomers alike.

£189 is quite expensive for the scope. You should be able to find it for £140-£150 if you shop around.

Nice job John. Proportions are now similar to my 12 inch

21 minutes ago, Barry-W-Fenner said:

All suggestions welcome John, I'm a bit proplexed as to why my views are not particularly good.

I purchased a short cheshire and the Baader click lock a couple of weeks ago, part of my reasoning for purchasing the click lock was to make sure the cheshire was central.

two of the 3 primary clips were showing clearly but the 3rd was minimal. I tweeked the secondary via my collimation knobs and got the 3 clips even. There was no actual loosining and moving of the secondary, just a slight adjustment on the screws. The primary was then quite far out, maybe 1cm from the dot to the ring in the primary. I got this lined up perfectly and put the scope away for the best part of two weeks 😕

I have used it the last couple of nights and stars are definitely not the bright points of light that they should be. Back ground stars are very dim/faint. Main stars like vega look like they would if you was slightly out of focus by a small amount, a bit blurry and not sharp at all. I will try to get a pic if I can tonight.

I will also run through the collimation process again to see if anything needs changing

Thank you

Baz

Just have a go at a basic star test on Polaris at around 250x. Rack though sharp focus and see if the image looks pretty much the same either side as the diffraction rings expand around what should be a fairly central dark secondary shadow.

35 minutes ago, bomberbaz said:

what mirrors are you using @John, could you have better quality mirror giving a superior view?  Don't even know if that is a possibility but just curious.

OO with a .987 strehl but I've had some great views with Skywatcher mirrors as well.

1 hour ago, Richard_B said:

Really interested in how you did the leg extensions on your AQ4 steel tripod. I could do with between 5" and 7" additional height so was considering your idea of new leg extension options. What did you do about feet for the new extensions? It looks as though the existing ones are fixed so I won't be able to transfer them over to the new extensions.

I would really like to do this rather then by the 16" EQ5 extension which is way more than I need.

Cheers

Richard

This is a really old thread (9 years) and @lexx has not posted on the forum since then. You might do better to start a new thread on your query and see if there is some other experience on the forum.