Voyager 3

Congrats ! Inform us how it turns out to you . 

Nice first light . Enjoy your new equipment ( wait , what? ) 

Have you looked through a Newtonian/dob before ? The planets don't have huge spikes and it's very subtle mostly. They don't extend much beyond 10-11" from the disc . 

But a TSA 102 might have spoiled you too much  .

On 25/09/2021 at 00:38, Franklin said:

Wow. No wonder the ancients started believing in Gods when they saw stuff like that in the sky.

  . 

Marvellous stuff Dave . 

3 hours ago, Don Pensack said:

Yes.  There are multiple reasons:

1) magnification.  A 1" separation at 180x is an effective 3' separation.

2) resolution.  1' is about the limit of resolution for the human eye.  A 4.5" telescope can resolve a 1" separation!

3) exit pupil.  Visual acuity is higher when the pupil used is smaller than the dark adapted pupil.  A 2-3mm exit pupil behind the eyepiece will allow your eye to resolve better than the full dark adapted pupil diameter.

Far fewer aberrations in the eye can be seen.

 

Many years ago, someone posted a chart I'll try to remember:

1' of arc--the limit of human vision

3' of arc--the typical limit for a person with good, but not superb, vision

4' of arc--the average resolution without strain--fairly easy for most experienced observers.

8' of arc--an easy resolution for the average eye without perfect correction of vision--just about everyone can see this easily.

How that translates:

a star with a 1" separation will be seen as double by the person with a resolution of:

1' at 60x

3' at 180x

4' at 240x

8' at 480x.

 

Perhaps that will give you an insight into why people need such radically different magnifications to split close double stars.

I can see ε Lyrae as double with the naked eye with glasses on.  In a scope, that translates to 78x to see all 4, and that is close to accurate--I can see all 4 stars at 83x fairly easily.

An easy split by everyone, though, might require 209x.  Certainly, seeing them all is much easier at the higher magnification.

People's eyes differ a lot, and scope quality and seeing can interfere as well, so there is no set magnification to see any double star.

 

 

And as you may know the ∆ mag of the double can affect the resolution even though it's not a direct factor . It is the direct result of the size of the airy disc .

Evenly matched pairs are a good test for resolving power of eyes / telescope / seeing . 

On 14/09/2021 at 19:53, oscar_camilleri said:

Lol , didn't know this existed. will look to invest in one of these, but i do have one of these as a backup. 

Be careful with it , not for use for small children . 

2 hours ago, jetstream said:

Totally agree and is my experience as well but with differing eyepieces.My Delos are sharp but there are sharper... it takes top optics and excellent seeing to bring out the differences IMHO.

Ps- what scope you using again?

It must be the TSA 120 !

I wanted to know why you northerners always complain about low elevation of planets in recent times . So one day in early August , I cooled the dob and pointed the scope soon after it got dark . Jupiter would have been at 10-15° altitude . 

My first reaction was no thanks . Bam ! What a blurry mess . The interesting thing was , the blurry , seeing effect was much more prominent and disturbing than the very mild bluish-reddish AD . Mind you , I never view the planets that low and I've never seen AD before on planets to be that much prominent , but still it wasn't the major factor in the poor views of Jupiter and Saturn . Fortunately I didn't feel the requirement of ADC , at least for my eyes , equipment and location .

Now now I feel pity for folks who live much Norther than me . Luckily this trend will improve in the coming years .

I remembered this thread in mind and I tried yesterday . I was easily able to tell Ganymede and Callisto were much larger than background stars ( and other 2 moons for that matter ) . I later checked SkySafari and confirmed that both the semi-point sources were indeed Ganymede and Callisto. It was a bit difficult to tell the extended nature of Io and Europa as one would expect from their sizes . 

It's fun and I recommend you try to see which are the moons comparing them to background stars before checking it with the software ! 

I used just 96× as seeing was bad but the lower power helped mitigating it . GRS too was visible ! 

5mm , 8mm , 12mm and the 15mm seem to be the pick of the lot .

On 12/09/2021 at 00:24, John said:

Collimation is key to resolving things, globular clusters included ,  assuming that the seeing is good .  

 

3 hours ago, John said:

The O-III is worth having for the Veil Nebula complex alone. There really is so much to see there

A UHC will show it but an O-III is has much more impact.

A good rich field refractor , a dark site , an OIII filter can keep anyone busy for a lifetime . The Veil nebula bubble helps too . 😀

52 minutes ago, Jiggy 67 said:

……..It’s neck and neck!!  Nothing to split between the UHC and 0III !!…….🤣😀

Then getting both the filter at the same time is the best solution to please all of us .  

Just kidding , buy either of them first , keeping in mind that you will be buying the other eventually . If you really get into this hobby and have a good dark site , a H-beta filter will be a good tertiary filter . 

Any comparo with your Morpheus and the Leica zoom @Stu ? 

If you will be getting both , then get the UHC first . It is more universal and will give a huge boost for the more famous nebulae like M8 , M17 , M42 , M16 etc . 

The  get the OIII for use with some supernova remnants , wolf -rayet excitation nebulae , large planetary nebulae etc . 

7 hours ago, Astro_Nic said:

Thanks - will take a look at the APM 9mm

It's weird as all the beginner guides say get barlows to reduce number of eyepieces, yet all the advice seems to be to not to bother......

So say I get all 100 degree APMs - what targets would I use for each of the sizes - 5mm, 9mm, 13mm and 30mm ?  Is that a good spread?  340x, 170x, 123x, 53x ?

What's the main difference between OIII and UHC filters?  Do you use both at once or just one at a time?

Are the APMs suitable for binoviewers if I went that way?  

 

Thanks!

You will be using a Paracorr II / paracorr for the best correction to use with 100° stuff . It adds 1.15× to the FL/ Focal ratio . 

So I take the FL as 1878 . 

Here is your spread with 30mm ( UFF )-13mm-9mm-4.75mm( really a 4.75mm approximately and not a 5mm ) . The 30mm can be substituted by the 20mm XWA  , if your site is light polluted . 

62× - 144× - 208× - 395×  . 

As you can see this is a good set until you reach the 9mm . It's a really big jump from 9mm to 4.75mm . 

A 6mm Ethos fits right in at 313× , but the 7mm APM XWA will also be a good step up at 268× . 

Now it looks like 

62× - 144× - 208× - 268× - 395× . 

Basically you may still need to fill the gap between 7mm and 4.7mm but it is down the list . A coma corrector like the paracorr II must be your first purchase . This assumes you already have good collimation tools . 

I hope others don't start reaction videos on this topic in YouTube 😂 .

Excellent report Paul . I love and absolutely agree with your last sentence -

"hearing excitement in her voice was music to my ears" .

7 hours ago, JeremyS said:

CCD is cooling, but thin high stuff has come in. 

Will probably put my 0.06m refractor out later.

Approximately 10 nanosecond cooldown time

Noooo ! It is 0.00000001 second cool down time  .

Has Jupiter become that large and bright ? I'm not able to see cloud bands . 🥴

6 hours ago, globular said:

"my heft is a sign of quality".

It was that way among the medieval aristocrats of France !!!

5 hours ago, Louis D said:

I know, but still, we can dream someone got a hold of a T7 prototype (or the mythical T3).

T0 ? 😎

Wonderful image @IB20 !

44 minutes ago, Stu said:

Depends what they go for!

Or where they go for ! 

It also shows the size difference btw the 4.5mm and the 17.5m which may be the extreme ends ! 

Lovely sketch ! I love the brightness and the uneven widths of the bands which gives such a realistic impression . I'm impressed .