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Halpha or Full Spectrum

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#1 Aaron_tragle

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Posted 07 December 2017 - 02:42 PM

This is something for the future, but which should I do; a full spectrum mod or a halpha mod for my nikon d5100



#2 jgraham

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Posted 07 December 2017 - 02:58 PM

I have DSLRs that are Baader (H-alpha) and full-spectrum modified. I have never used the full-spectrum part of the mod and I really don't see much benefit to it beyond some specialty applications.

 

Food for thought.


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#3 bobzeq25

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Posted 07 December 2017 - 03:21 PM

Amplifying.  People often think "full spectrum" must somehow be better.  In reality, the full spectrum gets you little more than the opportunity to buy a UV-IR cut filter.  The Ha mod has one built in, a real advantage.



#4 ImNewHere

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Posted 07 December 2017 - 03:40 PM

Unless you're going terrestrial FS and IR photography I'd go Ha.



#5 Aaron_tragle

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Posted 07 December 2017 - 07:01 PM

Ok thank you for the information, would it be wise to get a DSLR other than the D5100 to mod? I have heard the D5300 is better than the D5100, how is that so.



#6 bobzeq25

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Posted 07 December 2017 - 08:01 PM

Ok thank you for the information, would it be wise to get a DSLR other than the D5100 to mod? I have heard the D5300 is better than the D5100, how is that so.

The sensor is better, more sensitivity, lower noise.  The dark point has been raised from 0 (which cuts off half the bias) to 600 ADU.  That means better calibration frames.  Minor- the moire filter has been removed.

 

It all adds up to a substantially better camera for astro.  Given the cost of modding, and the low cost of the 5300, I'd recommend replacing the 5100.


Edited by bobzeq25, 07 December 2017 - 08:03 PM.

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#7 t_image

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Posted 07 December 2017 - 11:16 PM

This is something for the future, but which should I do; a full spectrum mod or a halpha mod for my nikon d5100

Beware of over-simplification of answers either way.

"full-spectrum" (a term that is a mis-nomer itself because UV is still quite impaired),

exists because it meets the requirements of a great number,

otherwise the option would not exists in the astro realm.

 

AP is about trade-offs and deciding what will give you and advantage and what disadvantages you can live with....

 

An easy benefit of "full spectrum" is it is easily obtainable with a DIY mod, no shipping/handling and fee that may be the price of another camera.......

A difficulty of "full spectrum" is needing to find a way to add a IR//UV block filter if your optical train has glass which allows the NIR light to increase chromatic liberation.

Those with reflectors that don't have a need for flatteners/reducers and have virtually only mirrors have less problem using a "full spectrum" sensor without evening needing a IR/UV filter...

Here's a random example of benefit: full spectrum allows you to use an IR pass filter for example with the Moon, which is a benefit to "seeing" issues and cuts down on chromatic aberration if one has a sub-standard refractor...

 

If you are interested in the pros/cons of each, I'd suggest you explore more threads on CN that has discussed this at length with a larger sample of people that are using both methods.....

 

From what I've seen from the many threads that ask this:

the individuals that want to understand why there may be an advantage to "full spectrum" and the cases for----

they might find a benefit.

the ones who could care less what the difference or understand the nuances but just want a simple way:

the h-alpha mod is for them.....

 

To me an analog is Mac (h-alpha) v PC(full spectrum) hardware. PC owners have more flexibility with customization, but with more complexity. Mac hardware owners are comfortable being at the mercy of the seller making permanent decisions for them.....

 

One note to ponder: "full spectrum" is a consistent term because it refers to there being no type of filter in front of the DSLR/ILC sensor.

"h-alpha" mod is a common concept, but depending on the transmission characteristics of the "h-alpha sensitive" IR/UV block filter placed in front of the sensor during the mod, the results may vary......

"full spectrum" allows the user to decide for themselves at a later date or even change their mind or add one newly developed....

 

To best satisfy the requirements of a customer, the best "modification" provider should ask more questions to you to help best point you in a direction and less about pointing you in a direction based on an opinion or a selective experience....



#8 17.5Dob

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Posted 07 December 2017 - 11:37 PM

Ok thank you for the information, would it be wise to get a DSLR other than the D5100 to mod? I have heard the D5300 is better than the D5100, how is that so.

The D5300 is a much better camera sensor wise. Also, if you want to try to use a D5100 coupled to a computer, it needs two cables to connect to it, vs the single USB cable that a D5300 needs, and the serial to USB adapter cable for the D5100 is ~ $100. Forget any cost savings going with an older camera.


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#9 Samir Kharusi

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Posted 08 December 2017 - 12:42 AM

The obvious advantages of a full spectrum mod:

IR photography using high shutter speeds:

123155705.jpg

 

Spectroscopy on a shoe string. Here's comparing the spectra of Betelgeuse and Rigel:

large.jpg:

 

Less obvious applications:

Video shooting in IR, here.

Cutting down the length of subs in hi-resolution lunar/planetary imaging. If you use a mirror scope you can opt for full-spectrum; thus doubling the fps of your video captures; the higher the frame rate you use, the more you can overcome seeing.

 

Unless you crave any or some of the above, steer clear of full-spectrum and just settle on Ha mod. Life is considerably simpler.


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