Louis D

3 hours ago, bemak187 said:

I am not  a reflector guy but I do prefer solid tube vs collapsible too.  I know when you get into bigger apertures the storage/weight becomes an issue but both of these are compact and easy to move around.

Agreed.  While I have a solid tube 6" f/5 alt-az Newtonian, I would never trade my 15" f/5 truss Dob for a solid tube Dob or EQ.  I actually helped setup an old Coulter 17.5" solid tube Dob once at a star party.  It required a full size van with a custom wooden floor cradle to get it there, and two to three people to unload and set it up.  It was very similar to the one pictured below:

Here's a good video showing the difference in planetary views between an f/8 6" achromat refractor and an f/5 6" Newtonian reflector, similar to your two options:

Since that dedicated astrophotography camera comes with a 1.25" nosepiece, it should slot straight into the 1.25" opening of the Barlow where an eyepiece would normally go.

For use in bino friendly countries, and if you have the budget, the Canon IS line might work well for you.  You'll be able to use higher powers without a tripod.

Your links link back to this thread.  Please correct them so we can better answer your questions.

To connect a Barlow to a camera, you'll need the following:

1. A T-ring for your camera:

2. Unless your Barlow has T-threads, you'll also need a 1.25" to T-thread nosepiece adapter:

3. Thread the 1.25" nosepiece into the T-ring, attach the T-ring to DSLR's mount, and then insert the assembly into your Barlow.

Generally, Barlows won't work with cameras with fixed lenses like cellphone cameras, all-in-one cameras, and P&S cameras.

2 hours ago, malc-c said:

Impressive launch, but shame that in the 21st century they couldn't have fitted cameras with downlinks to give us the same sort of images we get from Falcon 9 and SpaceX launches.

Blame some bean counter who didn't think it would be worth the added expense and didn't make it a contract requirement.

51 minutes ago, Zermelo said:

I think most of the Starguiders have that Smyth negative group in the base, which will prevent you screwing in a Barlow section properly. I don't have the BST Barlow, but the detachable part of my Baader x2.25 Barlow won't fit into the bottom of the Starguider 12mm.

I think the 18mm and 25mm lack elements in the lowest barrel, but I can't check for certain because I've loaned my set to my grown daughter to use.  Even if they lack those elements, the Baader still might hit the field stop diaphragm.

Most Barlow nosepieces don't have elements protruding above the threads like the Baader, so not an issue for most.

The bigger reason I wouldn't swap barrels is because dust gets inside and onto the bottom surface of the lowest lens of the upper group when you open up an eyepiece.  That surface is generally very close to the internal field stop location, so any dust on it is nearly in focus and very annoying.  It can be really difficult to get that lens surface factory clean again.

The lower Smyth (Barlow-like) group is an integral part of the eyepiece design.  Removing it and using the upper group alone would result in really poor correction and a much longer focal length.  You might be able to swap barrels within the BSTs, and see if you get anything usable.

I would probably go for the 12mm BST for 54x or 108x and exit pupils of 2.4mm and 1.2mm.  Both of these are useful magnifications/exit pupils.  That, and the 12mm performs very well at f/5.  The 25mm struggles quite a bit f/5.  26x with the 25mm BST isn't particularly interesting when you've already got 20x with the 32mm Plossl.

1 hour ago, Dark Adaptation said:

I'm sure it can't only be me that's noticed that the biggest and crudest rocket has USA in big red letters on it 🤣🤣

But the one that undeniably looks most like the male body part being alluded to is the Blue Origin New Shepard.  It's not always about sheer size when making a compensating statement via rocketry.  Sometimes, being literal makes a louder statement than being bigger.

10 minutes ago, DaveL59 said:

Now if there weren't a functional reason (as in fuel load) you'd start to think someone has a serious case of penis envy 😉

For those wanting to see it live, launch window for the roman candle starts 01:04 EDT, 06:04 UK time.

Personally, I like how the Statue of Liberty managed to move positions during the continuous shot without being caught on camera doing it. 😉

On 17/01/2019 at 03:47, thekwango said:

just thought i would update this for anyone interested. after much himming and haaing my mind was all but set on the Sky-Watcher SkyMax-127 AZ GTi until a 2nd hand Sky-Watcher Skymax 127 SynScan AZ GOTO popped up - managed to bag that for £225 - decent price i think (assuming the scope is in the advertised condition) 

All being well should arrive Saturday!

Looking back to pre-Covid and pre-inflation used prices, that's an awesome deal for that scope/mount combo. 

Glad you're able to start using it again.

My thinking as well.  Hopefully, it has a usable FOV at 10mm to 12mm of eye relief.  Any closer, and my long eyelashes grease the eye lens.  This assumes I take off my eyeglasses and live with my residual astigmatism at these small exit pupils.

1 hour ago, Prador said:

Currently £105.92 on the Svbony website if people are interested.

Aaarrrggg!  It's still $129.99 before sales tax here.  After subtracting VAT and converting, your price is $104!  All I can figure is the 25% extra tariff for stuff from a certain country is inflating the price here.

I love the big fields of view in my various 2" eyepieces for sweeping star fields.  I love 1.25" eyepieces for close-up views of smaller objects.  Each has their place, and I wouldn't be without either.

I did try to use the Bahtinov mask that came with one of my scopes for focusing, and I couldn't make out the lines well enough visually to be of any help.

@LaurenceT Here's the "trippy" view of Jupiter through my apodizing mask:

And here's the mask itself:

When buying diagonals, watch out for the ones with a curvy eyepiece holder.  They tend to have largish lips inside them restricting the use of widest field eyepieces in either 2" size for 2" diagonals or 1.25" size for 1.25" diagonals.  See the following thread:

1 hour ago, Nitecoda said:

This is what I'm considering, (prices EXCLUDE VAT):

• Tecnosky 102/700 F7 FPL-53 EDO APO Doublet £874
• Berlebach Spica Alt-Az Mount (£158) with 200mm shaft and a 3kg counter weight (£74)
• Ibis Obelisk Carbon Tripod with Ball Head (£265)
• APM 2" Prism Diagonal (£180)
• APM Super Zoom 7.7mm-15.4mm Constant 67° AFOV (£324)
• Baader Planetarium Sky Surfer V Red Dot Finder (£91)

Remember, FCD-100 is basically the same as FPL-53, only from Hoya instead of Ohara, so consider scopes using it as well.

Consider an FPL-51/FCD-1 102mm.  These are generally referred to simply as ED scopes.  It will save you some money if your budget is fixed, and will show increased color fringing only at higher powers.  It still won't have anywhere near the level of unfocused colors as in an achromat.  Even an FPL-53/FCD-100 doublet will show some false color at higher powers.  No refractor will ever be 100% color free like a pure reflector as with a Newtonian.  The Canon Digisuper broadcast zoom lenses come mighty close, but at a $200,000 cost.

Consider getting a sturdier alt-az mount that doesn't require a counter weight.  Why lug dead weight up that 200m hill?  Put that same weight into a better mount.

A GSO dielectric diagonal will probably be just as good visually as that prism diagonal starting out, but at much less cost.

A range of magnifications from 46x to 93x with the APM SZ would be fine for most observing, but you'd still want something wider to maximize your true field of view for objects like the Pleiades and for centering objects.  For higher powers, you might want to invest in a good Barlow as well.

I'd save a few bucks and get either a basic RDF or a Rigel QuikFinder instead of the Baader SF RDF.

44 minutes ago, HollyHound said:

Actually looking at the Astronomy Tools FoV calculator… the XW23 and XW30 are very close together on FoV, with the XW23 giving more magnification and better separation from the XW40 🤔

So perhaps the set becomes XW40, 23, 16 😀

I do tend to skip from a 40mm (Meade 5000 SWA, Pentax XW, or Lacerta ED) directly to either the 22mm NT4 or 17mm ES-92 (which have similar TFOV, 31.1mm FS vs. 27.4mm FS, respectively).  So yes, the XW23 might be a better fit with the XW40.

I'm guessing the XW23 will have a slightly larger field stop (FS) than the 22mm NT4, so maybe 32mm to 33mm.

1 hour ago, Carbon Brush said:

Who suggested a launch site in an area known for tropical storms?

Closer to the equator for a better launch boost, and the entire Atlantic Ocean to abort into.

Figure on increasing divergence from the distortionless calculated value the wider the apparent field of view (AFOV).  The divergence often increases even more if the eyepiece is very well edge corrected.

6 hours ago, bosun21 said:

I also ran a few short lengths of adhesive draught excluder on the tube for the magnets to sit upon. Works great 👍 

Is that the same as self-adhesive weather stripping?  I've never heard the term draught excluder before.  Must be a UK-US English thing. 🤷‍♂️

Boeing is the Artemis prime contractor.  They are a legacy defense contractor (think B-29s and F-15s).  They build to a spec from the government on a cost-plus basis.  They were required to do things a certain way as a result.  Everything has to work perfectly on the first launch.

SpaceX was self-funded, so they had a clean slate with which to start.  They used aggressive prototype development techniques.  Thus, all of the spectacular launch failures they've had.

Here's an anecdote of saving weight to increase payload.  Some SpaceX engineer did the numbers and questioned why they were using 4mm thick fuel tank walls when 3mm would suffice.  Tanks had always been that thick going back to the 50s.  Elon said, go ahead and make a tank 3mm thick, fuel it up and put it through the flight qualification tests.  It worked perfectly, and they saved 25,000 pounds that could be added to the payload instead.  By comparison, no Boeing engineer would have dared speak up because the culture is to always design to the government requirements.  Asking to change them would have taken years of back and forth between subcontractors, Boeing, and the government, and the engineer would have risked his/her career to even bring it up because it shows they're not a team player willing to go along with the herd.  Thinking outside the box is simply not in defense contractors' culture.

The lone exception are skunk works projects like the SR-71 and the Manhattan Project where defense contractors are given very high level requirements and are allowed to run wild with them with very little public oversight.