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4" Mak-Cass too small for Mars?

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#1 Shimonu

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Posted 07 August 2020 - 07:01 PM

I've just started with visual and AP this year. During the spring I sort bought a telescope out of desperation just to be able to observe. I had my first peek tonight at Mars but mostly got a slightly enlarged white ball. I would just like to confirm that my 4" is really too small to see Mars. There's no point in spending money on a new eyepiece towards that goal?


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#2 brentknight

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Posted 07 August 2020 - 07:06 PM

The short answer would be no...

But you will need some magnification (and good seeing) to bring out details. What are you using?

#3 Shimonu

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Posted 07 August 2020 - 07:09 PM

The short answer would be no...

But you will need some magnification (and good seeing) to bring out details. What are you using?

I have a Skywatcher Skymax 102.

I tried googling but I saw anything from 60-80 mm should be able to resolve Mars to needing 127mm/5"



#4 Tangerman

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Posted 07 August 2020 - 07:12 PM

What eyepieces do you have? Take your scope focal length and divide it by the eyepiece focal length, that'll give you your magnification. 



#5 Shimonu

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Posted 07 August 2020 - 07:18 PM

What eyepieces do you have? Take your scope focal length and divide it by the eyepiece focal length, that'll give you your magnification. 

I have the included 10 mm and 25 mm and I know about the rule of doubling your aperture in mm to get the maximum useful magnification. But as I understand it it's the aperture that determines if you can actually see any detail?



#6 jgraham

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Posted 07 August 2020 - 07:25 PM

It should be fun to use at opposition. I enjoy using my classic 60mm f/15 refractor on Mars at opposition and it does a fine job working at 100x. You might try using your telescope on Jupiter and Saturn right now. This might give you a preview of how it will work with Mars in the fall.


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#7 Barlowbill

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Posted 07 August 2020 - 07:26 PM

4" is pretty small for Mars.  And Jupiter, not to mention Saturn.  You should be able to distinguish Saturn's rings.  Very tiny.  I can easily do so with my 90mm ETX.


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#8 Shimonu

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Posted 07 August 2020 - 07:36 PM

Yeah, I've been able to look at Jupiter and Saturn. They do look quite breathtaking even if they're small. Just being able to recognize them, seeing the bands of Jupiter or the rings of Saturn is amazing. That's why I'm trying to figure out the limits of my scope and if it's worth investing in eyepieces for greater magnification



#9 fcathell

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Posted 07 August 2020 - 07:39 PM

I've seen the polar caps, Syrtis Major, Hellas Basin, morning limb haze, clouds over the Tharsis region and numerous other dark surface details on Mars at past oppositions with a 102 Mak.  You won't get a substantial size disk until about September. I was using a 6mm eyepice which would be 200+ X. The scope will have to be in excellent collimation, and the seeing should be steady. Most of your ability will be seeing conditions and temperature acclimation of the scope.

 

Frank


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#10 MaknMe

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Posted 07 August 2020 - 07:43 PM

Also, try waiting until morning to view Mars. It gets pretty high in the sky before sunrise. The higher it is, the better the views.
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#11 RyanSem

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Posted 07 August 2020 - 08:01 PM

Views will get better as we approach opposition in October!


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#12 brentknight

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Posted 07 August 2020 - 08:04 PM

I have an ETX-105 Mak, not used much lately.  I use my 4" refractor quite a bit more and it gives very nice views of Jupiter, Saturn - and I hope - Mars.  With any given eyepiece, you will get more magnification with the Mak, than I get with my refractor, but I get useful views at least up to 4mm (178x).  Like I said though, steady seeing will help quite a bit too.

 

If you sustain an interest in this hobby, you can never go wrong when investing in more eyepieces of good quality.  They can be used on any telescope you get in the future.


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#13 Redbetter

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Posted 07 August 2020 - 08:19 PM

Looks like we are playing 20 questions to get specifics about the gear.  Based on the description of eyepieces included I will assume this is the Skywatcher 102mm with 1300mm focal length rather than an ES 100 with 1400mm focal length.

 

I wouldn't expect a 10mm eyepiece to max out the above 102mm Mak, especially on Mars which has very high surface brightness.  That is only 130x.  An 8mm at 163x might be the effective optimum in good seeing, it somewhat depends on the observer. and what eyepieces are available. Some might prefer more, some less.  

 

At any rate, no, a 4" Mak is not too small.  Mars does require some decent seeing or else it can be a bright blur, which is essentially what you described.  I was looking at Mars last night at 173x with an ES 127Mak in mediocre seeing and there was quite a bit of detail beginning to emerge.  Detail like this is subtle, but once good focus is achieved and experienced observer will see it.  I probably should have put a red filter in to sharpen some of the dark features as this improves the contrast, but I was doing this unfiltered.  When the seeing is good I use 211x with that scope, which has been its effective planetary limit for my eye.

 

The usual questions are:  did you let the scope thermally equilibrate before observing?  Have you checked collimation at high power or done a basic star test just to make sure it has no major aberrations?  

 

Folks mistakenly assume that Maks never require collimation, mainly because it is an oft-stated myth that won't die.  Whenever a person gets a new scope, they should do a basic collimation check and star test to get an idea what they are working with. 


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#14 Tony Flanders

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Posted 08 August 2020 - 06:24 AM

I've just started with visual and AP this year. During the spring I sort bought a telescope out of desperation just to be able to observe. I had my first peek tonight at Mars but mostly got a slightly enlarged white ball. I would just like to confirm that my 4" is really too small to see Mars. There's no point in spending money on a new eyepiece towards that goal?

The key here is that you said you had your first peek at Mars "tonight" rather than "this morning." That implies to me that you probably viewed it shortly after it first rose in the east, which is about 11 p.m. at my location. You would need to wait another 3 hours or so for Mars to get up to a reasonable altitude above the horizon, around 2 a.m. In general, viewing objects close to the horizon is likely to yield fuzzy views -- though with Jupiter and Saturn this year, there is no other choice for observers at mid-northern latitudes.

 

Mars also appears fairly small now, at 15.5 arcseconds. It will be much easier to see details in October, when it's 22 arcseconds across. At that time, on a night of good seeing, your 4-inch scope should reveal quite a lot of detail at magnifications from 120X to about 160X.


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#15 JOEinCO

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Posted 08 August 2020 - 06:58 AM

I've just started with visual and AP this year. During the spring I sort bought a telescope out of desperation just to be able to observe. I had my first peek tonight at Mars but mostly got a slightly enlarged white ball. I would just like to confirm that my 4" is really too small to see Mars. There's no point in spending money on a new eyepiece towards that goal?

I'd say "yes"....you can certainly see detail on Mars with a 4" scope. I've had some great observing nights using a quality 80mm refractor, and just yesterday (in mediocre 2/5 seeing) the South Polar Cap and the darker area of Utopia were clearly visible. Around Utopia's perimeter the edges were sharp in some areas and faded out in others. So the detail at these apertures is there.

 

You'll want an 8mm to 6mm eyepiece to get the magnification in the 150X to 200X range, and as Frank said, you'll need a steady night since seeing conditions and a fully-acclimated scope are key. Your Mak-Cass needs the better part of an hour to come to thermal equilibrium.

 

But Mars is a bugger. He doesn't offer up eye candy like the Moon or Jupiter. You need to be patient and wait for the moments of good seeing. You have to be patient and train your eye.

 

 

It should be fun to use at opposition. I enjoy using my classic 60mm f/15 refractor on Mars at opposition and it does a fine job working at 100x. You might try using your telescope on Jupiter and Saturn right now. This might give you a preview of how it will work with Mars in the fall.

I have to politely and absolutely disagree with this approach. Use "now" to get behind your scope and get some experience. As I said above, I feel training yourself and gaining Martian experience is so important. If you wait for that line in the sand that is opposition, you lose all that opportunity. If you practice on 15 arc-second Mars now, imagine what you'll see on 22 arc-second Mars in October! waytogo.gif 

 

:::::::::::::::::::::::::::::::::

 

And as Tony just said, I wouldn't try Mars before bed as it's rising in the east. The window from 1:00-2:00am until dawn is much better right now.


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#16 Shimonu

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Posted 08 August 2020 - 07:48 AM

Looks like we are playing 20 questions to get specifics about the gear.  Based on the description of eyepieces included I will assume this is the Skywatcher 102mm with 1300mm focal length rather than an ES 100 with 1400mm focal length.

 

I wouldn't expect a 10mm eyepiece to max out the above 102mm Mak, especially on Mars which has very high surface brightness.  That is only 130x.  An 8mm at 163x might be the effective optimum in good seeing, it somewhat depends on the observer. and what eyepieces are available. Some might prefer more, some less.  

 

At any rate, no, a 4" Mak is not too small.  Mars does require some decent seeing or else it can be a bright blur, which is essentially what you described.  I was looking at Mars last night at 173x with an ES 127Mak in mediocre seeing and there was quite a bit of detail beginning to emerge.  Detail like this is subtle, but once good focus is achieved and experienced observer will see it.  I probably should have put a red filter in to sharpen some of the dark features as this improves the contrast, but I was doing this unfiltered.  When the seeing is good I use 211x with that scope, which has been its effective planetary limit for my eye.

 

The usual questions are:  did you let the scope thermally equilibrate before observing?  Have you checked collimation at high power or done a basic star test just to make sure it has no major aberrations?  

 

Folks mistakenly assume that Maks never require collimation, mainly because it is an oft-stated myth that won't die.  Whenever a person gets a new scope, they should do a basic collimation check and star test to get an idea what they are working with. 

Correct, it's the 1300 mm.

 

I didn't let it equilibriate first, however the temperature difference between inside and out was only a few degrees, I'm not sure how much that affects it? I haven't really done any check for collimation as I did hear Maks are rarely out of collimation. Have I understood it correct that you point at a star and make it out of focus so you get a disc and it should be even sized all around. I could do that a coming clear night.

 

The key here is that you said you had your first peek at Mars "tonight" rather than "this morning." That implies to me that you probably viewed it shortly after it first rose in the east, which is about 11 p.m. at my location. You would need to wait another 3 hours or so for Mars to get up to a reasonable altitude above the horizon, around 2 a.m. In general, viewing objects close to the horizon is likely to yield fuzzy views -- though with Jupiter and Saturn this year, there is no other choice for observers at mid-northern latitudes.

 

Mars also appears fairly small now, at 15.5 arcseconds. It will be much easier to see details in October, when it's 22 arcseconds across. At that time, on a night of good seeing, your 4-inch scope should reveal quite a lot of detail at magnifications from 120X to about 160X.

Alright, to come clear I noticed Mars as I was walking home after a night on the town with some friends and figured I had to take the chance to view it when I got home. So this was actually around 1.15 am and I thought it was decently high in the sky.

 

I guess I'll see if I can find an eyepiece around 7mm, check collimation, thermally equilibriate and wait for the best time during the night. Then give it another go. Thanks everyone
 



#17 Brent Campbell

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Posted 08 August 2020 - 07:53 AM

Yes you can see mars with a 4 inch but one important thing to remember is aperture rules.  You can coax detail out of a 4 inch or easily resolve it with an 8 inch or 10 inch.  The best view of mars that I ever had was through my c8.



#18 GR1973

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Posted 08 August 2020 - 08:10 AM

This depends mainly on the quality. With 3.5 high quality Mak or Apo you could see polar caps and Albedo features but you have you use at least 160x. This is my personal experience with my high end 3.5 Mak.



#19 JoshUrban

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Posted 08 August 2020 - 08:11 AM

Brent makes an excellent point - if you buy a new (or used) eyepiece, you can use it on any scope you may wind up with in the future.  I started with an 80mm refractor, and my practice on deep sky objects (not really a specialty for an 80mm) was very beneficial.  Not only was it fun then, but when I got bigger scopes, I took those to the limit, too.  (And for the record, bigger isn't always better.)  Sounds like you've got a great scope, and some great advice was given here.  Clear - and steady - skies to ya!



#20 Jon Isaacs

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Posted 08 August 2020 - 08:20 AM

Alright, to come clear I noticed Mars as I was walking home after a night on the town with some friends and figured I had to take the chance to view it when I got home. So this was actually around 1.15 am and I thought it was decently high in the sky.

 

I guess I'll see if I can find an eyepiece around 7mm, check collimation, thermally equilibriate and wait for the best time during the night. Then give it another go. Thanks everyone

 

 

Shimonu:

 

First, as others have said, your 102mm Mak is plenty big enough to see details on Mars.  And as others have said, waiting until Mars is well above the horizon is important.  

 

And realistically, planetary viewing after a night on the town is probably not the best way to get clear sharp views.  

 

Jupiter and Saturn are very low on the horizon from Sweden.  From Stockholm, Saturn and Jupiter never reach 10 degrees elevation so they are poor choices.  Mars reaches 32 degree elevation, much better, but you need to wait until it's nearly due south and near it's highest elevation to get the best views.

 

JOn


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#21 Redbetter

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Posted 08 August 2020 - 06:03 PM

Correct, it's the 1300 mm.

 

I didn't let it equilibriate first, however the temperature difference between inside and out was only a few degrees, I'm not sure how much that affects it? I haven't really done any check for collimation as I did hear Maks are rarely out of collimation. Have I understood it correct that you point at a star and make it out of focus so you get a disc and it should be even sized all around. I could do that a coming clear night.

 

Alright, to come clear I noticed Mars as I was walking home after a night on the town with some friends and figured I had to take the chance to view it when I got home. So this was actually around 1.15 am and I thought it was decently high in the sky.

 

I guess I'll see if I can find an eyepiece around 7mm, check collimation, thermally equilibriate and wait for the best time during the night. Then give it another go. Thanks everyone
 

With little difference in temp, cooling was not likely the issue.  Still, with a Mak or SCT it is usually best to give it some time outside before trying to observe.  This can be a bit more complicated in dewing conditions, where it might be best to keep the corrector capped while letting the OTA cool--that is what I did when I set my scope out to cool while I ate dinner, etc. when I lived in a humid climate.  After that, when ready to observe, I would uncap and put on the dew shield.

 

The problem with the "Maks are rarely out of collimation" myth is that it creates a bit of circular logic:  Folks often don't know if their scope is out of collimation, because they assume that it couldn't be, so they never check...therefore, Maks don't need collimation.  Meade took this so far as to make Maks that could not be easily collimated, because the rear housing/visual back contained  flip mirror and body that prevented ready access to the collimation screws.  The ETX's were considered to have very good optics, yet there were plenty of ETX's with collimation problems, and some of the replacements for these samples arrived with the same collimation problems.  Whatever state of alignment a scope had when it left a factory or someone else's hands, once it has gone through shipping and "handling", its state of collimation should be checked.  

 

With as far north as you are, the easiest star to use for collimation of a non-driven scope will be Polaris.  Polaris won't move rapidly in the field and this is important, since you need the star well centered in the eyepiece at high power to evaluate collimation.  If it is off to one side or the other the collimation will appear off.  After any adjustment, the star should be re-centered, before re-evaluation or further adjustment.  Adjustments should be very small.  Take notes about which screw was turned and how much, clockwise or counter-clockwise.  If you find you went the wrong direction, reverse it.

 

The star only needs to be moderately out of focus to get a useful doughnut, don't rack it way out as this makes it more difficult to see smaller collimation errors.


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