Lukehurst-Nichol classic dobsonian modifications

[Stu]

Looking fabulous Piero!

[FenlandPaul]

Very exciting indeed! Breeze is dying down. 

What have you used to collimate, Piero?

[Alan White]

Looks wonderful Piero,

good luck with tonight.

 

[antariksha]

Piero, heartiest congratulations. It is an exciting time for you now. 

Clear skies!!

[Piero]

1 hour ago, FenlandPaul said:

Very exciting indeed! Breeze is dying down. 

What have you used to collimate, Piero?

Thank you, Gentlemen!

 

Paul, I use the Glatter's collimation tools, like in the photo below. I have the 650nm version plus tublug. Very happy with them.

 

Edited June 28, 2019 by Piero

[John]

That looks a sophisticated collimation device - mine is a cheapo plastic cheshire

 

[fireballxl5]

7 hours ago, John said:

That looks a sophisticated collimation device - mine is a cheapo plastic cheshire

 

Yes but a very useful device! I've only recently started using one to collimate a 16" f5 Dob and it's a great improvement when setting up on your own 🙂

[Pig]

Ermmm it looks like I might have to revisit my long awaited DOB purchase 🔭

[Piero]

Last night the new dobson saw its first light! 

In summary, I really enjoyed using it, it surpassed my expectations, and I will have a learning curve with it due to many new variables to me.

My objective was to view certain targets that I am familiar with, rather than jumping into new things. First of all, I checked the collimation of this telescope using the Glatter's tools mentioned above. The secondary was already spot on from last time I checked it. This despite the fact that the telescope was dismantled and mounted back again. The primary mirror only required a very minor tweak. Cooling time. Well, my inexperience really. I took the telescope outside, but I left it vertically. Therefore, there was little chance that the mirror had cooled down properly by the time I started observing (about 11:00 pm). Therefore, when I started, there was variable astigmatism, CA, and coma visible across the field and more towards the edge. After about 45m, the view was stable, astigmatism was completely gone, same for CA, and coma was minor but noticeable from 70% of the fov using the 20mm Lunt HDC (100 deg). 

Targets:

I started off with Jupiter (I know, the telescope was not cooled down properly, but that is when I realised my mistake). There was still quite a lot of detail going on, with features appearing and disappearing all the time. One thing that was striking to me was that the axes due to secondary spider were very minor. My other 8" dobson F6 I have in Italy is a disaster in comparison. In this new dobson, the axes are certainly not in the way. Even when observing bright stars, I didn't find the axes distracting at all (@jetstream I re-checked my secondary mirror. The centre of the secondary mirror is at exactly 7", exactly half UTA internal diameter). I will need more sessions for this target. I completely forgot to buy the AA batteries for the telrad (new tool for me), so I used only the RACI finder (another new tool for me) for finding object. Having some experience with the TV-60 helped, but the TV-60 was used on its own, not on top of a 6ft telescope (another first time tool for me). A few times I was puzzling on the actual pointing of the telescope. Just lack of experience, really, and it will improve with some practice. Currently, a step ladder is still in my purchase list, as I preferred to wait for the telescope first. Unfortunately, this means that targets above about 75-80 deg were not really accessible for my height. So, for the time being, I opted for Delphinus, a small but bright constellation, with a lovely double star (gamma) and a globular cluster C47. I am glad for this choice as it allowed me to have some pre-training on pointing the telescope and star-hopping an easy target with it. This globular cluster is quite small and the bright nocturnal sky at the moment does not help either. Said this, it was still enjoyable to revisit a target spotted a few years ago. From Delphinus, I moved to the old globular cluster M15, which looked outstanding, completely covered with stars. I am not a guy who swaps many eyepieces during a session, but this time was a bit different as the telescope is new and it's also important to see how the eyepieces behave (e.g. all reach focus). Shortly, yes, all my eyepieces reach focus, including the ZZ+VIP. With the latter, there isn't much travel left, but still enough. David added a 0.5" moonlite spacer, so if more backfocus is needed in the future, I can always take that spacer off. At 150x the cluster was majestic, what a sight. I believe I spent a good 45 min only on this target. Other targets were M39, M31, M32 (man, how bright this was!), M110. The Duck Cluster was absolutely beautiful at 150x. I've never seen it so big and detailed. A memorable view, really. Finally, Saturn was visible down South. It was 3am, so quite late for a proper observation. Still, the Cassini division was nicely visible, with a few moons around, a faint one (I didn't check the moon position TBH), 2 distinct belts and a faint one, the shadow of the rings on the planet - all in all it was very good. Tracking the targets at high power was very easy. The axial movements are really smooth but with good stiffness. I like that.

Take home messages (for me): 1)  I need to get a short ladder so that I can observe close the zenith with 1 step, and sit on the 2 or 3 steps when the telescope is pointing very low, 2) get the batteries for the telrad (!), 3) cool down with inclinated telescope, 4) (totally personal consideration) although I like my 20 Lunt optically, I'm still not that trilled by 100 deg AFOV and instead find the ultra large FOV distracting and tiring. I much prefer up to 80 deg.

 

Question for Moonlite users: I've always forgot to ask this.. do you use all the 3 screws for locking your 2" eyepieces or you took off one and just use 2 screws? Are 3 screws really necessary? 

Edited June 29, 2019 by Piero

[jetstream]

4 hours ago, Piero said:

Last night the new dobson saw its first light! 

In summary, I really enjoyed using it, it surpassed my expectations, and I will have a learning curve with it due to many new variables to me.

Awesome Piero!

Great first light, this scope will give many fine obs sessions for years to come!

[John]

Good stuff Piero - glad to hear a positive report

I'm surprised that you see much coma at F/6 though. It's hardly noticable at all with my F/5.3 even with the Ethos eyepieces - at most just a touch right where the FoV meets the field stop.

I cool my 12 inch at a 45 degree angle but it's useable pretty much straight away at low to medium powers.

 

[Piero]

2 minutes ago, John said:

Good stuff Piero - glad to hear a positive report

I'm surprised that you see much coma at F/6 though. It's hardly noticable at all with my F/5.3 even with the Ethos eyepieces - at most just a touch right where the FoV meets the field stop.

I cool my 12 inch at a 45 degree angle but it's useable pretty much straight away at low to medium powers.

Thank you, John.

The view was not terrible at low power when cooling down, but it was not great at 150x which was the mag when I started.

Regarding coma, well, I do see coma in all my telescopes, including the Tak-100. It is quite contained, I have to say, but is still visible. Of course, the eyepiece showing the most amount of coma is the 20 Lunt, and it is more visible with bright stars as the spread area is larger. Not a big deal for me, as I rarely observe at the edge, particularly with a 100 deg eyepiece.

[Highburymark]

Congratulations on your new scope Piero - it's always interesting and educational to read your posts and reports

[Stu]

Great start Piero, sounds like every detail has been taken care of by some sound planning and a very experienced maker. I'm sure you will have many happy nights to come.

I think I share your views on 100 degree eyepieces. I have the APM 20mm and it is excellent, but would be just as excellent at 82 degrees for me.

[John]

Perhaps what we need is for the manufacturers to re-vamp their 82 degree ranges so that they achieve the positive characteristics of the 100's that are now around with a more modest AFoV for those who prefer that. There are continued rumours across the pond of a Tele Vue "Nagler 2" design sporting an 85 degree AFoV and better eye relief across the range but nothing concrete as yet.

Vixen nearly achieved something great with their SSW range but IMHO some small but annoying issues have held them back.

A topic for a different thread though !

 

 

[Stu]

A revised Nagler 85 degree with the same contrast etc as the Delos would do me fine I think.

[antariksha]

Piero, I am glad things are working out well. You have one of the best collimation tools. I use the same make. Its superb.

Good to read your detailed report on your viewing. It will be fun and addictive to watch DSOs in this now.  Clear skies.....

[Piero]

I was not aware of the plan/idea of a new Nagler 85.

My case is even simpler.. the 30mm, 12.5mm, and zoom I have, cover all my cases, really. As Stu said the 20mm Lunt is excellent, but in my case at least, I could perfectly live without. 

[FenlandPaul]

What a cracking first night, Piero! Sounds like you made the right choices in getting familiar with it. I’m sure you’ll warm to the telrad/RaCI combination soon; I find it brilliant (I have the Antares versascope 10x60) and so intuitive. It won’t be long before you move “as one” with your scope.

Roll on the dark nights!!

[Piero]

2 hours ago, FenlandPaul said:

What a cracking first night, Piero! Sounds like you made the right choices in getting familiar with it. I’m sure you’ll warm to the telrad/RaCI combination soon; I find it brilliant (I have the Antares versascope 10x60) and so intuitive. It won’t be long before you move “as one” with your scope.

Roll on the dark nights!!

Thank you, Paul.

actually, the RACI finder is something I've been thinking of for a while but having no experience with it, I preferred to wait and get the telescope first. 

How do you get on with a 10x60? It could be quite handy under skies with some light pollution. I'd also like the idea to change eyepieces if needed. Plus, there is a chance the TV60 will go.......

[Trikeflyer]

Fabulous. What a great session. You have an awesome scope there. Keep us posted on how you get on with it. You might tempt us to invest in something from David and David. 😱

Steve 

[Piero]

24 minutes ago, Trikeflyer said:

Fabulous. What a great session. You have an awesome scope there. Keep us posted on how you get on with it. You might tempt us to invest in something from David and David. 😱

Steve 

Good choice! Will do.

Piero

[FenlandPaul]

10 hours ago, Piero said:

How do you get on with a 10x60? It could be quite handy under skies with some light pollution. I'd also like the idea to change eyepieces if needed. Plus, there is a chance the TV60 will go.......

The 60mm really packs a punch, and RACI means I don’t have to do mental gymnastics with a star chart (usually Interstellarum). My telrad is really a glorified red-dot the way I use it; I rarely use the circle diameters ⭕️ for anything.

Using the TV60 for a finder would be incredible!!

[niallk]

Great stuff Piero - nice to hear tracking targets at high power was easy and the structure felt stiff.  This makes the world of difference at the EP in use - something i really found with my 15" vs my 250px.  Enjoy revisiting everything - those globs really pop with increased aperture!

Edited June 30, 2019 by niallk

[niallk]

+ I also really like the natural wood finish look