jetstream

12 minutes ago, JOC said:

I've often thought a useful thing would be a novices list of say 20 interesting things to see up there (and roughly the right time of year to view - say before midnight) and the sort of magnification that they support to get the best view - most novices could then do the maths for their own F/L and work out what their best EP's would be to get close to that 'magnification' out of what they own.

Thank you.

This is a great idea, but is there a chance that the listed parameter magnification could be changed to exit pupil for extended objects?

This is because magnifications can change enough with (f ratio and aperture) that we could well be out of the range to view the extended objects- nebula in particular, espc with filters.

An example of this is with the f7.5 SW120ED- I use a 42mm Vixen LVW on the Veil with and without filters- the same eyepiece in my 10" is not so good for this. the "optimum" mag for the 120ED is 21x and for the 10" 44x at the same 5.6mm exit pupil.

This also illustrates "image scale" as related to me by mod @swamp thing years ago.

Anyway, the concept is excellent for the list

Just now, JOC said:

Ah, so it's a fairly big target

I sure hope I don't come across as a know it all, I just try to relate my experience that has been built on the help from others.

The HH notch will not really show as "big" in your scope.

It is an empty "thumbprint" in the funnel of IC434. Seeing IC 434 is an absolute must to first see the HH. I would practise seeing this first, which will then up your chances on B33, a dark nebula aka the Horse Head.

Your 32mm plossl is right in the strike zone but you need a good,tight high transmission Hb.IMHO.

I truly enjoy seeing others advance their observing skills.

2 hours ago, JOC said:

Maybe I can try to find that too.  I don't know what other kit you've got, but if you can find it using purely visual astonomy with a 17.5mm I must have a combination with my 8" F6 that will provide similar 'magnification'

JOC, S&S is at about f4, you are at f6- IMHO an exit pupil of a very minimum of 4.3mm to 5.5mm + is needed. In your scope a 30mm-32mm plossl is a good bet, you also need scatter control and a narrow FOV to keep Alnitak at bay.

S&S large focal length naturally narrows the view (controlling Alnitak) even with widefields and his f4 gives a 4.3mm exit pupil with the 17.5mm. On top of this, the image scale in his 20" allows more flexibility.

My 10" dob likes a 25mm TV plossl and the much needed Astronomik Hb on the HH.

Of course these are just my thoughts on things but the HH notch is visible in an 8" with all ducks in a row. Over on S&S NGC 3003 thread there is good info on dark adaptation etc, all critical to see the HH.

Good luck!

1 minute ago, Paul73 said:

To move the turntable and thus adjust the height you undo a thumb screw and twist the whole top.

 

On mine I loosen the thumbscrew and then use it to turn the top- can you do it like this?

2 minutes ago, Paul73 said:

PC1

Just wondering, it also has that adjuster knob? I would imagine you can use it the same as the PCII for set up and use. Doing it this way takes all the thinking out of its use which I like!

1 hour ago, Paul73 said:

Thank you all for your advice. 

Despite the obvious charms of wider viewing. I’m going to go for a second hand  Delos 14mm and hope to try a ES92° Or APM eyepiece at a star party in the near future. 

Paul

For what your doing this is a superb choice. Btw- do you have the PCI or PCII?

Hickson 44 is waiting for you! Its pretty cool actually, love those clusters.

1 hour ago, JOC said:

I guess a hood might help if I was settled down for a good spell at a single target, but I still tend to charge around like a bull in a china shop chopping and changing and every time I get up the stray lights nearby probably ruin any dark adaptation that I have achieved.

Anything you can do- light shields, position behind something, hoods will help. When dark adapted you will be able to easily see in open areas even in true darkness. Anyway, all these things will compliment your fine scope and eyepieces and bring out the best in them.

Btw, M82 is a great place to play around upping the mag in stages and M81 goes opposite (unless you want to emphasize its core) with the goal of eventually seeings its spirals, IMHO. M81's spirals are fickle.

Even here, under dark skies and with large dobs I can make features disappear if wrong eyepiece choices are made. You will not be lacking with those Baaders and their top notch coatings...

Eagerly waiting reports!

15 minutes ago, JOC said:

Perhaps its because I wear spectacles to observe

For me eye cups provide a way to shield the eyes from stray light, thats pretty much it. Your specs prevent this needed (IMHO) function.

Do you think an observing hood (hoodie) could benefit you?

Using one might prevent your pupil dia from bouncing around, allowing you "half" dark adaptation or better. Your eyepieces are superb, nothing else needed here- time to look at other ways to increase contrast etc, IMHO.

Getting good views is a process.

Just try a bunch of things Robert, doing this will allow you to predict what eyepiece you might need. These days I enjoy pulling out feature in objects like M33, M101, NGC 2403 and a whole host of others. Your big dob will do the same. Very happy to get structure in Markarians Chain.

There are a couple of observers that have really advanced their observing skills, yourself and @Littleguy80 kudos to you guys, it really takes work and determination.

28 minutes ago, Ships and Stars said:

the sky's and the object's surface brightnesses are affected equally.

they are dimmed equally... a "contrast" expert would bounce up and down with misconceptions- believe me I know lol!

Making a galaxy larger makes it easier to see up to the trade off point of illumination of the eye.

First off Mark has been a true help in my pursuit of viewing galaxies, he is an excellent galaxy man.

Second, viewing galaxy cores can be different (take much more mag) than the more diffuse galactic cirrus.

To illustrate Marks and Clarks point M51 is a great observing lab, and one which Clark uses. This object has been a mainstay of mine with many tens of hours spent on it. When you view M51 with lower mag the spirals will be buried in galactic glow. Its the same as seeing NGC 3003.... lower mag increases visibilty because of its nature.

Upping mag on M51 reveals much more defined spirals - my 15" will take 228x at f4.8 on it. Differing mags enhance differing features because there are visible features that can be enhanced.

Some galaxies have no more visible features so mag must be adjusted accordingly, lower in the case of the large NGC 3003. Take a small galaxy core and I've gone way over 400x.

I just ran across this in Markarians Chain on NGC 4402- low mag revealed a hint of structure, more revealed true mottling.

1 minute ago, Ships and Stars said:

Thanks for the links to Clark & Blackwell

Do you want a VG practice ground to illustrate Marks comment? his note supports Clarks idea. I have practised this concept quite a bit.

@Ships and Stars I must also emphasize the conclusion-try everything and then let experience be your guide.

"What Does All This Mean?

To see all the detail in an object, use many powers, from very low to very high, examining the entire object with each magnification. Because the OMVA appears to be a shallow minimum, one need not be precisely on the optimum. Within a factor of 2 or a little less in magnification is fine. A magnification sequence of: 35x, 50x, 80x, 120x, 180x, 270x, 400x ... (a sequence increasing magnification by a factor of about 1.5) is great."

18 hours ago, Ships and Stars said:

I think in hindsight, it's a lot trickier here getting dark adapted in town than I've considered. 

It can be very hard, for me too. One look at a light even 800 yds away can wreck things. Thing is I seem to chemically adapt faster now, going from dark blind to full seeing (can see in the dark) in about 15 mins. So I do believe that repeated true dark adaptation speeds things up, however this assumes we havnt wrecked our eyes during the day.

Another thing- totally agree with Mark about the lower mag thing- I always sweep the area with the 20mm Lunt and more recently the 17.3 Delos, which is superb for this. I like seeing the field stop on faint, small galaxies- that dark edge seems to enhance perceived contrast on these ones, assuming the EP is good in the first place.

Thing is all these little tricks are a personal thing and for general, relaxed fun viewing I like hyperwides, espc on nebula. I really don;t like seeing the FS on these objects, globs either.

Have you read Clarks take on things or Blackwells? More needed pieces to fill in the puzzle.

"Optimum Magnified Visual Angle

A low-contrast object is more easily detected if it is larger. For an extended object such as a galaxy viewed in a telescope, magnification does not change the contrast with the background, because both the sky's and the object's surface brightnesses are affected equally. Some visual observers have stated that a dim object's contrast with the sky background increases with higher magnification, but this is clearly wrong. The contrast merely looks greater because of the increased detection capabilities of the eye. Clark (1990) coined a name for the maximum magnification that will help detection: the "optimum magnified visual angle" (OMVA)"

https://clarkvision.com/visastro/omva1/index.html

Excellent.

Observing in less than ideal conditions will enhance your abilities under more optimum skies.

The SW "Super 25" can be good, ours is surprisingly good. The 10mm MA got tossed into the circular file cabinet....

@John is right about a 2" 28mm-30mm eyepiece being a huge asset to you IMHO. BST's are well regarded upgrades and the Vixen SLV's another step up. 3 nicely good eyepieces and a barlow will serve you well. Its hard to go wrong with a Baader10 BCO and their "Q-Barlow".

If I am in the sun all day or watch the LED TV my dark adaptation can really suffer, even way later on. M42, Sirius, Jupiter etc wreck my adaptation too- the Sky Commander dim green screen is in question too. Lots to think about if trying to get the faintest ones dancing into view.

Many of the most serious DSO observers promote the use of the observing hood, which can help keep out stray, eye wrecking light.

12 minutes ago, Ships and Stars said:

red LED on nipping over to the EP case, so there's a good chance I didn't settle with it enough to re-adapt fully.

On top of transparency and lowish darkness you might have wrecked the chemical part of dark adaptation...

From Vogel: "Dark adaptation

Let's summarize this:

	Opsin, which if formed after a light event from activated rhodopsin is weakly active and makes the photoreceptor cell "see" virtual light even in complete darkness and prevents thus complete dark adaptation.
	Only after about 30 minutes, opsin is completely regenerated to inactive rhodopsin, allowing complete dark adaptation of the cell.
	Dark adaptation relies mostly on the switching-off of the activity of opsin and only to a very minor degree on the increase of the total amount of rhodopsin by regneration."

Just now, Ships and Stars said:

Conditions

This was the issue IMHO.

The magnitude scale is not linear "The scale is logarithmic and defined such that each step of one magnitude changes the brightness by a factor of the fifth root of 100, or approximately 2.512"

There is a massive difference between 20.3 and 21.3 mag skies IMHO and every bit past this is that much darker.

Of course with galaxies we also have size and therefore surface brightness considerations and the more I learn about galaxies the less I realize I know. Listed magnitudes are derived from flux magnitudes have a couple of formulas to convert to "V" mag. Some shapes seem harder at the same size and mag IMHO.

The best on this is @mdstuart IMHO.

Congrats for seeing this under challenging conditions Robert.

There are different fluxes with their own number, NGC 3003 is a bright 6x1.3 is arc min (large) galaxy right around mag 12. It is easy in my 10"..

Orthos can take getting used to on these objects- eyeplacement in particular IMHO.

http://simbad.u-strasbg.fr/simbad/sim-id?Ident=ngc3003&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id

21 minutes ago, Ricochet said:

Definitely. The 9 or 12.5 are probably the best bets. 

Yes totally agree and for me I tend to go a bit lower yet using a 17mmish across my range of dobs.

7 minutes ago, JOC said:

I did hope it might be solution to teasing out the E and F in the trapezium

Excellent eyepieces JOC.

Would it be worth a try to lower the magnification for "E" and "F" in the trap? I find these mag sensitive for some reason as are some other stars- counter intuitive I know.An example of this is the central star in M57, for me anyhow.

3 hours ago, Littleguy80 said:

I have the 13mm APM and like it very much. However, for Stephan’s quintet I use my 9mm BGO. As Gerry said, orthos are the way to go for faint objects. The small FOV is a worthwhile sacrifice for the sharpness and contrast you get with a good ortho. It sounds like the Delos are a good compromise. Wider FOV than an ortho but closer to ortho performance than the APM. 

Nice choice Neil, you have a great set up. These days the 17.3 Delos and 10 Delos are getting a good workout, the comfort is hard to beat. In any case all the eyepieces mentioned in this thread are VG options IMHO.Hard to go wrong.

15 minutes ago, Paul73 said:

I love the galaxy clusters like Stephen’s Quintet or ARP 316 cluster, but want to get the best from single galaxies like M51

The Docter is not needed.

I can tell you what I do on these- for serious Stephans Quintet observing the orthos come out.I was just observing ARP 316 (Hickson 44) with the Delos and Docter.

For these kinds of objects the Delos is a top choice as are orthos.

If you like M51, M101, M33 and NGC 2403 a wider FOV is nice.

Actually for what you want to do I'd pick the 14mm Delos with the PCII. Just saw your reply to Don P...I set the PCII on A focus the 21E (or 20mm Lunt) the focus all other eyepieces with the PCII adjuster...

You can use a Delos to pre set the PCII as well. IMHO the PCII adds contrast.....

2 minutes ago, Paul73 said:

So I need both?

I was worried that it would be a case of striking a Quality vs FOV balance.

Paul

I actually use the Docter UWA 12.5mm in this role-best of both worlds. I do have a hankering for the 13mm APM...I find Delos constricting on all but galaxies.

Can you give a specific example of what you want to observe?

6 minutes ago, Paul73 said:

Interesting John. If it was a choice between Delos and Ethos, it would be Ethos all the way. But is the APM a match for the Delos quality wise? I’d rather sacrifice a bit of fov for better quality.

Paul

Its extremely hard to match the Delos transmission and contrast in a 100 deg EP, including the Ethos IMHO. However the Ethos contrast is excellent and if my 20mm APM HDC is any indication the 13mm should be very close to the 13E.

For viewing experience the 13mm HDC would be my choice and for close examination of threshold galaxies etc the Delos would get the nod.